UltraFire LC 14500 protected Li-ion battery, generally been used for laptops, digital cameras, flashlights ect is a good power supplier.
Built in protected PCB to protect the battery over charged or discharged.

Features:
1. Rechargeable high discharge rate,  no "memory" effect
2. Short circuit and over current protection
3. Long cycle life environment friendly
4. The voltage of full charge & empty condition is 4.2v & 2.75v respectively

Specification:
Model: LC 14500
Capacity: 900mAh
Voltage output: 3.6V
Size(mm): 50(Length) x 9(Diameter)
Color: Silver grey
Unit packing gross weight: 40g

Note:
Do not dispose in fire or heat
Do not puncture, damage, and disassemble
Full charge the battery to store if long time no use