Battery Holder 1 x 18650 Lithium 3.7 Volt Rechargeable BatteryFeatures:Black Plastic Holder with 5 Inch Wire LeadsHolder Has One Mounting Holes so it Can be Secured in Place if NecessaryTakes 1 Standard Size 18650 Lithium BatteryCompact Battery Pack of 3.7 Volt Output (Battery Not Include)Polarity Marks in Battery CaseDimensions: 2-15/16″ (L) x 13/16″ (W) x 3/4″ (H)UNKRP13941