LG HE4 18650 2500mah 35A*  3.7v rechargeable lithium battery.

Safe chemistry Li-MN 3.7V rechargeable battery does not require protection circuit. These cells can handle high amperage and is safe to use in series / multi-cell applications. Max pulsed discharge 35A, max continuous discharge 20A. Can be charged with any Li-Ion battery charger with 4.2V output. Price is per single cell (1x)

• Brand Name: LG
• Size: 18650
• Model: LG 18650-HE4
• Type: Li-Mn (High Drain)
• Rated Capacity: 2500mAh
• Max Pulsed Discharge 35A
• Max Continuous Discharge 20A
• Nominal Voltage: 3.6V
• Peak Voltage: 4.2V
• Dimensions: 18.3mmX65mm
• Rechargable: Yes
• Protected: No
• Chemistry: Lithium manganese Dioxide (Li-Mn02) 
• Style: Flat Top
• Color: Yellow

NOTE: Use special caution when working with Li-ion cells, they are very sensitive to charging characteristics and may explode or burn if mishandled. Make sure the user has enough knowledge of Li-Ion rechargeable batteries in charging, discharging and assembly before use. Always charge in/on a fire-proof surface. Never leave charging batteries unattended. We are not responsible for damage if there is any modification of the batteries/chargers in any form or shape (including pack making). We are not responsible for any damage caused by misuse or mishandling of Li-Ion batteries and chargers. We only recommend using Lithium Ion rechargeable batteries with a control circuit (protection PCB) to assure safe charge, discharge, etc, use of lithium ion batteries with a protection circuit is potentially hazardous.

Official specifications:

• Nominal Capacity: 2,500 mAh
• Nominal Voltage: 3.6V
• Standard Charge: 1250mA, cut off: 50mA
• Fast charge: 4000mA, cut off: 100mA
• Max. Charge Voltage: 4.2 +/-0.05 volt
• Max. Charge Current: 4000mA
• Standard Discharge: 500mA
• Fast Discharge: 10000mA, 20000mA
• End voltage: 2.5 volt
• Weight Max.: 47.0 g
• Operating Temperature: Charge 0 ~ 50°C, Discharge -20 ~ 75°C
• Storage Temperature: 1 month -20 ~ 60°C, 3 month -20 ~ 45°C, 1 year -20 ~ 20°C