Description: 7.2V 4200mAh 18650 Smart Lock Lithium Battery Product No.: HG4AE2552 Cell model:  18650 / 2100mAh / 3.6V        Battery Specification: 2s2p / 4200mah / 7.2V     Nominal voltage: 7.2V         Nominal capacity:  4200mAh Charging voltage:  8.4V         Charging current: 840mA Discharge current: 840mA Maximum discharge current: 2100mA   Discharge cut-off voltage: 5.5V     Internal resistance : ≤ 180m Ω       Delivery voltage: 6.8-8.0V    Battery weight: 230g Product size: 90 * 72 * 37mm (max)   Operating temperature: Charging temperature: 0-45°C; Discharge temperature: -20-60°C Storage temperature environment: 1month - 20-60 ° C; 3months - 20-45 ° C; 12months - 20-25 ° C Relative humidity: 65 ± 20% Battery structure: Lithium Battery protection: short circuit protection, overcharge protection, over discharge protection, over current protection, etc Application field: Smart Lock, smart home deviced powered by Lithium Battery