ARB-L21-5000 V2.0 is a high-capacity 21700 Li-ion rechargeable battery built for more power and longer runtimes. Additional features include a protection circuit in the anode to help prevent short circuits, over charge/discharge and over heating. Pressure relief vents which expel waste gas in the rare case of an internal short circuit preventing an explosion. Battery capacity up to 5000mAh. 500 charging cycles.Important Note: THIS BATTERY IS NOT COMPATIBLE WITH 18650 FLASHLIGHTS OR OLDER STYLE CHARGERS. COMPATIBLE CHARGERS ARE THE FENIX ARE-A2, ARE-A4, ARE-D1 OR ARE-D2.Specifications of the ARB-L21-5000 Rechargeable BatteryNew 21700 battery type5000mAh high capacityProtection circuitry to prevent short circuitsPressure vents to prevent explosions500 charge cyclesCurrently compatible with the E35 V3.0, HT18, LR35R, LR50R, PD36R, PD36 TAC, PD40R V2.0, TK16 V2.0, TK20R V2.0, TK22 UE, and TK30.Capacity:5000mAhVoltage:3.6VCharging Current:Recommended 1A, maximum 5AWeight:2.6 ounces (72.5g)Size:Length: 2.99 (76mm) Diameter: 0.85 (21.5mm)Warranty Period:12 month from date of purchaseWARNING: Cancer and Reproductive Harm -www.P65Warnings.ca.gov