272 DIODES
312 DIODES
302 DIODES
HAIR & SKIN
SKINCARE ESSENTIAL
PATENTED TECH
#1 Korean Collagen Mask
5 MODELS
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Not sure where to begin?
Whether you're researching laser therapy for the first time or ready to choose a model, our hair growth experts are here to help. Browse quick-start topics below or book a free one-on-one consultation.
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Help me choose a model
How LLLT works
Is Kiierr right for me?
Who benefits, hair types, skin tones, age, and medical considerations.
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Which model should I choose?
Compare all models: 148 Pro, 272 Premier, DualWave, 302 UltraFlex, and 312.
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Growth guarantee & returns
Our 7-month money-back guarantee, registration, and refund policy.
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Accepted payment methods, FSA/HSA, and financing options.
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Mirrored Battery
Mirror battery with four indicator lights on top and a power button. Twist-lock connector between cap cable and battery.
Battery A
Gray Battery
Gray rectangular battery pack with a flip switch on the top. Connects to cap via USB cord with a twist-lock connector.
Battery C
New Black Battery
Soft flexible cap design. Battery has four indicator lights. Cable connects via white arrow alignment. 6- minute daily sessions.
Battery D
Select your battery above to see troubleshooting steps specific to your device.
30 min every other day
USB cord connector
Flip power switch
Twist-lock on cord
Charging
Lasers not turning on
Shutting off early
Beeping
Cord & connection
Cap fit
Usage & sessions
How to charge Battery C / D correctly
1
Turn the battery to the OFF position before connecting the charger. If the battery is ON during charging, the charger light stays green but the battery will not actually charge.
2
Plug the battery into the charger and into a wall outlet. A red or blue light should appear on the charger (red = older models; blue = newer models), confirming charging is in progress.
3
During charging, no lights will appear on the battery pack itself — only the wall charger indicator will be lit. This is completely normal.
4
After 8 hours the charger light turns green. New models auto-cutoff at 95% — all four indicator lights glow solid for ~5 minutes then go out. This is a safety feature, not a malfunction.
5
Unplug the charger from the battery completely before use. The cap will not turn on while the charger is still connected.
Charge Battery C/D after every 3 uses for best long-term battery health.
What the four indicator lights mean
4 lights solid = fully charged
3 lights = approximately 75% charge
2 lights = approximately 50% charge
1 light = approximately 25% — recharge soon
Beeping + no lights = critically low — auto-shutoff imminent to prevent battery damage
During charging, the indicator lights on the battery itself will NOT be lit — only the wall charger shows status. This is by design for Battery C/D models.
Battery is on but lasers are not turning on
Ensure battery is fully charged and the charging cord is completely unplugged before use.
Connect the cap and battery cable by lining up the prongs on the two small connectors, then secure by screwing the black plastic lock piece clockwise until tight. A loose connection is the most common cause of the cap not activating.
Place the cap on your head. The safety sensor will not allow the lasers to activate unless the cap is worn on the scalp.
Turn the battery to ON and press and hold the power button. You may notice the laser lights flashing on and off — this is the pulsing method and is normal, not a malfunction.
If the cap still doesn't activate, turn off, disconnect the twist-lock, wait 1 minute, realign prongs, reconnect securely, and try again.
The pulsing (rapid flashing) of the lasers is intentional and part of the treatment delivery method for Battery C/D models. This is correct behavior.
Battery shuts off shortly after turning on
Charge the battery for a full 8 hours with the switch in the OFF position. A partial charge is the most common cause of early shutoff.
Ensure the charging cord is fully unplugged before turning the battery on.
After a full charge, turn on and verify the indicator lights show 3–4 lights (strong charge level).
Check the twist-lock connector — a loose connection can trigger the safety shutoff. Disconnect, realign prongs, and relock firmly.
If shutoff persists, email service@kiierr.com with a short video showing the behavior.
Battery C/D models include automatic power-off when charging completes and a low-charge beeping alert during use. Both are protective features and are not defects.
Battery is beeping during a session
After approximately 7–9 uses, beeping during a session is the low-battery reminder. Finish your session if possible, then turn off and recharge fully.
If you don't turn off after beeping begins, the device will continue alerting for 10–15 minutes then automatically shut down to prevent over-discharge damage.
The battery reserves a 5% safety buffer — this is why it may appear to shut off before the charge indicator shows empty. This protects the battery cells.
Simply recharge fully after the low-battery beep and resume your next session on schedule. This will not affect your treatment progress.
Battery is beeping but the cap hasn't been placed on my head yet
This usually means the cap connection is not being detected. Disconnect and firmly reconnect the twist-lock connector (prongs aligned, locked clockwise).
Always place the cap on your head before pressing the power button — the safety sensor requires scalp contact.
If beeping continues with cap properly worn on a full charge, there may be a sensor or connector fault. Email service@kiierr.com with a short video.
Cap only works when the cord is at a specific angle
Locate the twist-lock connector (two small arrows on the cord). Unscrew the lock piece fully, wait 1 minute, then reattach with prongs aligned and screw clockwise firmly.
Also check the battery end of the cable — disconnect, wait 1 minute, reconnect firmly.
While powered on, gently wiggle the cord near each connector. If the cap cuts in and out, the connection is loose or damaged at that point.
Route the cord with no tension or sharp bends at either connector during use.
Intermittent connection indicates connector wear or damage. Gray Battery C charging cord replacement: use code CHARGING at kiierr.com/replacement-parts ($8.99). Contact
service@kiierr.com if unsure which cord type you need.
Can I plug the cap directly into the wall while waiting for a replacement?
No — never connect the cap directly to a wall outlet. The cap is designed to operate only with the Kiierr battery pack. This is dangerous and voids your warranty. Order a replacement
at kiierr.com/replacement-parts using code BATTERY at checkout ($24.99 for Battery C/D).
Cap is sitting high on my head
The standard MD cap fits up to 23.5" in circumference. The MD Elite fits up to 24.5". The cap does not need to be an exact fit — the lasers have adequate range to reach the scalp even if the cap sits slightly higher.
Part your hair to reduce volume before placing the cap.
Gently place the cap — do not force it tightly down.
A stretch fabric headband can help hold the cap securely without forcing it.
If you have the standard MD and need more room, contact us about upgrading to the MD Elite. Return just the laser cap and ball cap (cords/battery are compatible with both) for a $200 upgrade.
Will the cap treat areas it's not directly covering?
No — lasers only treat scalp areas in direct contact with the diodes. The 272 MD and MD Elite are designed to cover the crown and front hairline. If you're concerned about your specific hair loss pattern and coverage, contact our support team.
30 minutes every other day on non-consecutive days. Do not use more than once per day. Use consistently for at least 7–12 months, then continue 1–2 times per week as a maintenance regimen.
Is it normal for the lasers to flash (pulse) during my session?
Yes — the pulsing (rapid flashing on and off) of the lasers is the correct and intended behavior for Battery C/D models. This is the pulsing method of LLLT delivery and is not a malfunction.
This is the content for tab panel #1. You can replace this content with whatever you'd like inside the first panel.
This is the content for tab panel #2. You can replace this content with whatever you'd like inside the second panel.
This is the content for tab panel #3. You can replace this content with whatever you'd like inside the third panel.
Twist-lock connector
4 indicator lights
Pulsing laser method
Battery is not charging
Make sure the battery flip switch is in the OFF position before plugging in the charger. If the switch is ON during charging, the charger indicator appears to work but the battery will not actually charge.
Plug the charging cord into the battery and into a wall outlet. A red light should appear on the wall charger, confirming charging is in progress.
If no light appears, unplug both ends, reconnect securely, and try a different wall outlet. Avoid power strips and surge protectors.
Charge for a full 8 hours. After 8 hours the charger light should turn green, indicating a full charge.
Once fully charged, unplug the charger from the battery completely before use. The cap will not operate while the charging cord is still connected.
Only use the original Kiierr charging adapter. Third-party chargers are not compatible and may damage the battery or prevent charging.
Battery indicator light behavior explained
During charging, no lights should appear on the battery pack itself — only the wall charger indicator will be lit. This is completely normal for Battery A/B models. Battery lights only illuminate during active use.
If the charger shows green immediately when plugged in without first showing a red charging phase, the battery may not be accepting a charge. Try the battery reset steps in the
"Shutting off early" tab, then attempt a full 8-hour charge again.
Ensure the battery is fully charged for 8 hours and the charging cord is completely unplugged from the battery.
Flip the battery switch to ON. Press and hold the power button for at least 3 seconds.
Place the cap on your head before powering on — the cap has a built-in safety sensor that prevents the lasers from activating unless the cap is worn on the scalp.
Check the USB cord connection. Disconnect the cord at the USB port on the battery, wait 1 minute, then firmly reconnect.
Also try disconnecting at the twist-lock connector (marked with two small arrows). Unscrew the middle lock piece, wait 1 minute, reattach, and screw clockwise until secure.
The lasers are subtle — in bright light they can be hard to see. Cup your hand around the inside of the cap in a dim room to confirm whether they are actually on.
Battery keeps beeping but lasers won't activate
Beeping typically means the cap is not properly detected or the battery charge is critically low. Disconnect and firmly reconnect the cap cord first.
Always place the cap on your head before pressing the power button — the sensor requires scalp contact to activate the lasers.
If using a newer Battery A/B model: beeping during use (after approximately 7–9 sessions) is a low-battery alert. Turn off and recharge fully before your next session.
Power off completely, wait 30 seconds, put the cap on your head, then power on and hold the button for 3 full seconds.
Newer Battery A/B models include a low-charge beeping alert to prevent over-discharge damage. If you hear beeping while the cap is running, recharge the battery fully before your next session.
Turn the battery ON while it still has some remaining charge, then press and hold the power button for 10 seconds to reset it.
Let the battery sit in the OFF position for 60 seconds after the reset.
After the rest period, charge the battery for a full 8 hours. Try a different wall outlet if you haven't already.
After a full charge, press and hold the power button until the battery lights up, release, then press once more to power on the cap.
If shutoff persists after a full charge and reset, the battery is likely defective — submit a warranty or replacement request.
The battery reset resolves most early shutoff issues. Always perform the reset and a full recharge before concluding the battery needs replacement.
Cap only works when the cord is held at a specific angle
Locate the twist-lock connector on the cord (marked with two small arrows). Unscrew the middle lock piece fully, wait 1 minute, then reattach and twist clockwise until firmly secured.
Also disconnect the USB end from the battery port, wait 1 minute, and reconnect firmly.
While the cap is powered on, gently wiggle the USB portion of the cord near the battery port. If the cap cuts in and out as you wiggle, the connection is loose or damaged at that point.
Route the cord so there are no sharp bends or tension at either connector end during use.
A cord requiring a specific angle to maintain connection indicates connector damage. Replacement cords are available at kiierr.com/replacement-parts — use code CAPCORD for the USB cap cord or CHARGING for the charging cord ($8.99 each).
Can I plug the cap directly into the wall while waiting for a replacement battery?
No — never connect your Kiierr cap directly to a wall outlet. The cap is designed to run only from the Kiierr battery pack. Wall connection is a safety hazard and voids your warranty. Order a replacement battery at kiierr.com/replacement-parts using code BATTERY at checkout ($14.99 for Battery A).
Standard 148 Pro and 272 caps fit heads up to 23.5" in circumference. The cap does not need to be an exact fit — there is no significant loss of effectiveness if the cap sits slightly higher. The lasers have adequate range to reach the scalp.
Gently place the cap on your head — do not force it down tightly.
Use a stretch fabric headband to help hold the cap securely without forcing it down.
After 7 months of consistent use with no results, you're still eligible for the growth guarantee return. Make sure your device is registered within 45 days and you have your before photo on file.
No — the lasers only treat scalp areas in direct contact with the diodes. The nape, behind the ears, and lower back of the head will not receive treatment during a session. The 148 Pro and 272 caps are designed to cover the crown and front hairline where androgenetic alopecia most commonly occurs.
How often should I use the 148 Pro or 272 Premier?
30 minutes every other day on non-consecutive days. Do not use more than once per day — follicles need recovery time between sessions for LLLT to work. Use consistently for at least 7–12 months for best results, then continue 1–2 times per week as maintenance.
Can I use the cap on wet hair?
No. Always use the cap on completely dry hair. Wet hair blocks laser light from reaching the scalp and can damage the electronic components. Towel-dry and fully air-dry before every session.
Using the cap on wet hair can cause electrical damage and will void your warranty.
Is shedding normal in the first few weeks?
Yes — increased shedding in the first 2–6 weeks is normal and expected. LLLT causes weak hairs to shed so stronger new growth can replace them. Do not stop treatment during this phase. If heavy shedding continues beyond 3 months, contact our support team.
Soft flexible cap design. Battery has four indicator lights. Cable connects via white arrow alignment and twist-lock. Sessions are 6 minutes daily. Device beeps once at startand three times at end of each session.
6 min daily
Flexible cap design
White arrow alignment
1 beep on / 3 beeps off
Dedicated AC adapter required
Unexpected shutoff
Sessions & beep codes
Usage & care
How to charge the 302 / 312 battery correctly
Plug the AC adapter into the battery and into a wall outlet. While charging, the indicator lights on top of the battery should flash — this confirms charging is in progress.
If no lights appear at all, unplug both ends completely, reconnect securely, and try a different wall outlet.
A full charge is complete when all four indicator lights stay on solid without blinking.
Disconnect the AC adapter completely from the battery before use. The battery will not power the cap while the adapter is still connected.
What the indicator lights mean during charging
Lights flashing = fully charged = charging in progress (normal)
All 4 lights solid = fully charged — disconnect adapter now
No lights when plugged in = connection issue — unplug and reseat both ends of the adapter
No response after full charge = battery may need replacement — contact service@kiierr.com
Ensure battery is fully charged (all 4 lights solid) and the AC adapter is completely disconnected.
Connect the battery and cap cable by aligning the small white arrows on both sides of the connector, then twist clockwise to lock firmly. Misalignment or a loose lock is the most common cause of activation failure.
Place the cap on your head. The 302/312 has a built-in sensor — lasers will not activate unless the cap detects scalp contact.
Press and hold the power button for at least 3 full seconds. You should hear one beep and see the red indicator light — this confirms the lasers are active.
If the cap doesn't respond, check that it's sitting flat on your head. Even a slight gap can prevent the sensor from detecting contact.
The red indicator light is your confirmation that the lasers are working. Cup your hand inside the cap in a dim room to visually confirm laser light if you're unsure.
Cap is not responding at all when powered on
Confirm all 4 battery lights are solid (fully charged). If not, recharge fully first.
Disconnect the cap cable fully, wait 1 minute, realign the white arrows, and reconnect with a firm clockwise twist.
Double check that the AC adapter is fully unplugged from the battery.
Press and hold the power button for a full 3–5 seconds without releasing early.
If the battery shows no response at all after a confirmed full charge, it may need replacement. Email service@kiierr.com with a short video showing the battery connected to the charger and then connected to the cap during a power attempt.
Treatment stops unexpectedly mid-session
Check battery charge — a low battery can cut the session short. Recharge fully and test again.
Check whether the cap shifted on your head mid-session. The sensor requires continuous scalp contact — a slight shift can interrupt the session.
Adjust the cap back into position and press the power button to restart.
If sessions consistently stop early on a full charge with proper placement, reconnect the cable (white arrows aligned, firmly locked) and retest.
A complete 302/312 session is exactly 6 minutes. At the end you will hear 3 beeps and the device shuts off. If you hear 3 beeps before 6 minutes are up, the session was interrupted — it does not count as a full session.
How to use the 302 / 312 — step by step
Fully charge the battery until all 4 indicator lights are solid. Disconnect the AC adapter completely.
Connect the battery to the cap cable by aligning the white arrows on both connector ends and twisting clockwise to lock.
Place the flexible cap on your head with clean, dry hair. Press gently to conform to your scalp.
Press and hold the power button for at least 3 seconds. One beep = device started, lasers active. Red indicator light confirms treatment is in progress.
After 6 minutes: three beeps = session complete. Device shuts off automatically. Use daily for best results.
1 beep at startup = device started successfully, lasers active
3 beeps at 6 minutes = session complete, device shutting off normally
Beeping without activation = cap not properly seated on head, or cable connector is loose
Continuous beeping / no start = error — check connection and battery charge; contact support if it continues
Cap fit and coverage for the 302 / 312
The 302 UltraFlex and 312 DualWave use a soft, flexible design that conforms more naturally to different head shapes than structured cap models.
Place the cap so the laser panel makes maximum contact with your scalp.
Use your hands to gently press and shape the flexible cap closer to the scalp where gaps exist.
The flexible material allows you to mold it into position — unlike structured caps, there is no need to force it down.
The flexible design is one of the main advantages of the 302/312 — it adapts to your head rather than requiring you to adapt to it.
No — lasers only treat scalp areas in direct contact with the diodes. The 302's higher diode count provides more comprehensive scalp coverage than lower-diode models. Areas with no direct diode contact will not receive treatment.
Can I use the 302 / 312 more than once a day?
No — there is no evidence that additional daily sessions produce faster or better results. The 6-minute daily protocol is clinically optimized for this model's output and diode count. Using it more than once per day is not recommended.
No. Always use the cap on completely dry hair. The cap is an electronic device that can be damaged by moisture, and wet hair blocks laser light from reaching the scalp effectively.
How do I clean my 302 / 312 cap?
Wipe the inside of the cap with a slightly damp cloth and allow to air dry completely before storing or using again. Do not submerge in water or machine wash. Avoid harsh chemicals or alcohol-based cleaners on the laser diode surface.