The Hikoki BSL36B18 MultiVolt Battery is a dual voltage battery that can be used on both 18V power tools as well as 36V Tools. When used on a 36V power tool, it provides 4.0Ah of power while when on an 18V tool, it provides 8.0Ah. This means that, when fitted to a compatible power tool, a power output of more than 1000 Watts is achievable. The battery is built with a Multiplex Protection Circuit MPC for overload, overcharge, and over-discharge prevention, ensuring safety and long life. No memory effect means you can charge it anytime for optimal convenience. Experience superior power and worry-free performance. The Hikoki UC18YSL3 Multivolt Fast Charger is compatible with 14.4V, 18V and 36V Hikoki Slide-on batteries. The charger has a cooling function so that the battery stays at the optimum temperature when charging . This is designed to prevent the battery from overheating resulting in a longer battery life. It will not charge a hot battery until it has cooled therefore protecting both the user, tool and battery. The two colour indicator light informs at what stage charging is at. Charging time can be between 15-38mins subject to battery.