A replacement 3.6v Ni MH (nickel metal-hydride) battery for the Gtech SW05. The 3.6v Ni MH battery that powers our SW05 sweeper models is powerful & rechargeable. Over several years of use around the home, however, it can start to lose its power, resulting in reduced runtimes. With this replacement 3.6V Gtech battery, you can ensure your unit delivers optimal sweeping performance, wherever you're sweeping in the home.