A very useful accessory for you, with water-resistant and durable rubber case, can be used for bicycle light, headlamp, etc.

Features:
Portable and large capacity.
This battery pack is made up with 4 batteries.
Original TrustFire replacement battery pack for headlamp and bicycle lamp.
Waterproof design with the special waterproof connector and durable rubber case.

Specifications:
Model:18650 battery pack(4*18650)
Material: Lithium
Voltage: 8.4V
Capacity: 4800mAh
Charging time: 5-6 hours 
Rechargeable times: Up to 300 times
Item weight: 239g / 8.43oz
Item size: Approx. 7.8 * 4.1 * 4.1cm / 3.07 * 1.61 * 1.61in

Package List:
1 * 18650 Rechargeable Lithium Battery Pack
1 * Battery Pack Bag