Fenix Rechargeable Battery 18650 3.6 Volt Lithium 3500 mAH

From MidwayUSA

Batteries and chargers from Fenix deliver consistent output across sizes, with rechargeables and chargers built for the task. Matched to the standards of Fenix flashlights, headlamps and bike lights, these products combine safe operation with reliability even in adverse conditions. The Fenix ARB-L18-3500 is a high capacity 18650 Li-ion rechargeable with a protection circuit in the anode to help prevent short circuits, over charge/discharge and over heating. The battery also includes pressure relief vents which expel waste gas in the rare case of an internal short circuit preventing an explosion.