Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Welcome Offer : Use Code WELCOME5 for 5% OFF your first order!
Free Shipping on Most USA Orders
Some products sold on this website may expose you to chemicals known to the State of
California to cause cancer, birth defects, or other reproductive harm.
All electrical products must be installed by a qualified electrician in accordance
with local wiring regulations. Incorrect installation may result in fire, electric
shock, or injury.
Always disconnect power at the circuit breaker before installation.
💡
Bulb & Usage Advisory
Do not exceed the maximum wattage specified on the fixture label.
Keep away from flammable materials. Allow adequate ventilation around the fixture.
Keep out of reach of children. Not suitable for wet locations unless rated IP65 or higher.
The Fenix ARB‑L21‑5000U is a high-capacity 21700 rechargeable Li‑ion battery delivering 5,000 mAh of reliable power for high-drain flashlights and gear. Equipped with a built-in USB‑C charging port, you can recharge it quickly with common USB‑C cables—no separate charger required. Ideal for extended runtime and convenience.
Safety is front and center: it features comprehensive protection circuitry (overcharge, over-discharge, short-circuit, and overheat protection), as well as pressure relief vents for safe energy release. The button-top design ensures compatibility with a wide range of devices. Rated for 500 charge cycles, it maintains dependable performance over time.
Key Specifications:
Capacity: 5,000 mAh, Nominal Voltage: 3.6 V
Charge Rate: USB‑C port, up to 5 A max (standard 1–2 A recommended)
Design: Button‑top format, 73 mm long, ~21.6 mm diameter, ~72 g
Warranty: 12‑month manufacturer coverage
A robust and convenient power solution—perfect for tactical flashlights, headlamps, outdoor gear, and emergency devices.
Shipping Note: Lithium ion batteries are considered "dangerous goods" per US transportation regulations and can often only be transported via ground shipment. Orders containing loose batteries will typically take much longer than predicted to be delivered. Delivery times of 14+ days are not uncommon.
⚠️ WARNING (California Proposition 65): This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, please visit www.P65Warnings.ca.gov.
The Fenix ARB-L21 is a solid rechargeable battery, but I did have to wait longer than expected for it to arrive. Once I got it, it performed well in my flashlight, but the shipping could be faster.
S
Sofia Martinez
Great upgrade for my flashlights
Switched to the Fenix ARB-L21 5000U from some older batteries, and I can tell the difference! This one holds a charge much better and doesn't seem to drain as quickly. Very pleased with this purchase!
H
Hiroshi Tanaka
Not impressed, stopped working
I was excited to try the Fenix ARB-L21, but it stopped holding a charge after just a few weeks of use. Maybe I got a defective one, but I expected more for the price.
O
Omar Al-Sabah
Decent battery, but instructions were unclear
The Fenix ARB-L21 is decent, but I struggled with how to charge it at first because the instructions weren't very clear. Once I figured it out, it worked fine, but I had some initial confusion.
P
Priya Hill
Instructions were unclear
Spent a while figuring out the wiring because the manual is poorly written. Once I got it going the lights look nice, but the setup experience was frustrating.
WELCOME5: Use code WELCOME5 for 5% off on your first order
