The Electronic Rat Killer is designed to kill rats quickly & humanely with an electric shock. Controlled by electronics, when a rat enters the electronic rat killer, it steps across two plates and completes an electrical circuit, which kills the rat in seconds. The Electronic Rat Killer is ideal for use in a variety of settings such as domestic, agricultural, horticultural? & many others. Four C-size batteries (not included) provide enough power for up to 12 kills. Warning light signals when batteries need replacing. Also kills mice. A warning light signals when the device has been activated so that the remains can be removed and the trap reset. Full instructions for use provided.