The XTAR 18650 Rechargeable Li-ion Battery is a lithium-ion cell with a protection circuit that's commonly used in torches.

Specs:

• Nominal Voltage: 3.6V
• Voltage Range: 2.75V – 4.2V
• Capacity: 2600mAh
• Max Continuous Discharge: 5A
• Watt-Hour Rating: 9.36Wh
• Over Charge/Discharge Protection Circuit: Yes
• Weight: 48g
• Cycle Life: ~ 600 charge/discharge cycles