Power tools are all tools that are used by means of an electric drive. They simplify the work to be done. Predominantly these tools are hand-guided but also stationary machines are used. Electric tools are e.g. drilling and grinding machines, jigsaw and circular saw, screwing tools for example: cordless screwdriver. These are available in different performance classes as well as corded or battery-powered. Battery tools increase the mobility enormously and make power tools operational in any terrain.