ARB-L21-5000U is a high-capacity 21700 Li-ion USB rechargeable battery built for more power and longer runtimes. This battery has its own USB-C charging port for quick/easy charging without the need for a separate charger. Additional features include a protection circuit in the anode to help prevent short circuits, overcharge/discharge, and overheating. Pressure relief vents expel waste gas in the rare case of an internal short circuit preventing an explosion. Battery capacity up to 5000mAh. 500 charging cycles. This product will only work in those models supporting 21700 batteries. A USB-C charging cord is NOT included. 5000mAh high capacity USB Type-C rechargeable battery Protection circuitry to prevent short circuits Pressure vents to prevent explosions 500 charge cycles The indicator light on the battery is red while charging, blue when charged Currently compatible with the HT18, LR35R, PD36R, PD40R V2.0, TK22 V2.0, TK22 UE, and TK30. Capacity: 5000mAh Voltage: 3.6V Charging Current: Recommended 1A, maximum 5A Weight: 2.6 ounces (72.5g) Size: Length: 2.99? (76mm) Diameter: 0.85? (21.5mm)