Small but engineered for endurance: the ARB-L18-4000U combines high capacity with integrated USB-C charging in a button-top 18650 format suitable for high-performance flashlights. The USB-C port removes the need for external chargers (use a quality cable and power source), while protections for short circuit, overcharge, over-discharge and overheating provide safer charging and operation. Steel rivet construction and a safety vent reduce risk of swelling or catastrophic failure. With up to 500 cycles retaining about 75% capacity, this battery is an excellent spare for premium Fenix lights or for users seeking autonomy and convenience without external chargers.

Technical specifications

Type: 18650 rechargeable, button top.

Rated capacity: 4000 mAh.

Charging port: integrated USB-C.

Protections: short circuit, overcharge, over-discharge, overheating protection.

Charge cycles: up to 500 cycles (≈75% capacity retention).

Mechanical safety: steel rivet construction and safety vent.

Recommended use: high-power LED flashlights compatible with 18650 cells (verify device compatibility).

Included: 1 battery.

Not included: USB-C cable, external charger, power bank.

Package contents

1 × Fenix ARB-L18-4000U 18650 rechargeable battery (4000 mAh).

User manual and safety leaflet.

Protective packaging.

Benefits for the user
High runtime and convenient USB-C charging: less gear, more usable cycles and integrated safety features make this battery ideal for intensive flashlight use in professional and outdoor settings.

Safety & usage warnings (GPSR / Italian compliance)

Read the supplied manual before first use and follow all instructions.

Keep battery and accessories out of reach of children.

Use only in devices designed for 18650 cells and always verify compatibility with your flashlight or equipment.

Recharge only via the integrated USB-C port using reliable, certified cables and power sources; avoid damaged or uncertified chargers.

Do not short circuit, puncture, disassemble or expose the battery to fire, extreme heat or liquids. Do not use if the cell is damaged, deformed or swollen.

Do not mix new and used batteries or different chemistries; do not use external chargers incompatible with 18650 cells unless manufacturer permits.

Remove the battery if the device is stored for long periods; store in a cool, dry place away from heat.

Dispose of spent batteries per local regulations for batteries and WEEE; do not discard with household waste.

It is forbidden to tamper with, modify or permanently alter the battery or its protection systems. Unauthorized intervention can compromise safety, cause malfunction and void warranties.

In case of overheating, unusual smell, leakage or other abnormal signs, stop use immediately, isolate the cell safely and seek qualified assistance.

For extreme-condition use (very hot or cold environments), follow manufacturer guidance and local safety rules.