21V Lithium Ion Battery 4.0Ah Brand: ELAIK Battery type: Ternary lithium Nominal voltage of a single battery: 3.7V Charging voltage: 21V Battery capacity:4000mAh Discharge voltage: 14V Charging current: ≤1C Sustainable discharge current: 5C-10C Working temperature: charging: 0~55℃, discharging: -40~75℃ Storage temperature: -40~125℃ Storage humidity: ≤85%RH Protection board: Built-in overcharge, overvoltage, and overcurrent protection board, balanced charging circuit (ensure that each battery is fully charged before disconnecting) 4000mAh/10 knots, product size: L:119*W:75*T:65mm Product weight: 588g Scope of application: Used for a variety of power tools: electric wrench, electric angle grinder, electric hammer, electric chainsaw, handheld lawn mower, battery module, large-capacity, high-pressure water gun, powerful car vacuum cleaner, garden saw, electric drill, polishing machine, etc.As long as the battery interface is consistent; Note: If there is a situation where the battery socket is not clear: please consult customer service!