A replacement 4.8v Ni MH (nickel metal-hydride) battery for the Gtech SW05. The rechargeable 4.8v Ni MH battery that powers our SW05 models provides long runtimes & powerful performance. However, with several years of use sweeping & cleaning your home, it can lose its power. This impacts efficiency & can result in reduced run times. If you've had your Gtech SW05 for a while, & you've noticed a dip in the run times, why not get it back to its very best with this replacement?