Features and Benefits: Rechargeable Lithium Polymer pack; Lithium polymer battery features charge status indicator; Enables the Double Clutch to run 3 hours and 30 minutes on high and 10 hours on low; Enables the Double Clutch to produce 125 lumens high and 30 lumens low; This battery is a USB rechargeable lithium polymer pack. The battery features a charge status indicator to allow the user to know when the battery is fully charged. One battery is includedwith the purchase of a Double Clutch headlamp. The battery allows the Double Clutch to run 3 hours and 30 minutes on high and 10 hours on low. Enables the Double Clutch to produce 125 lumens on high and 30 lumens on low.