Probably one of the the best battery switches in the world. Prevents from battery discharge on longer storing periods. Works as well as a reliable mechanic anti theft device. Easily installs onto your battery ïn a few minutes: No mecanical skills required. Suitable for all kind of 6, 12 and 24 volt electrical systems up to 350 amps in cars, lorrys, vans, trucks, SUV, campers, boats, farming machines, classic vehicles etc. Easily clamp mounted directly on the negative (-) terminal of the battery. No need to cut any cable or carry out any aditional electrical installation. Power is disconnected by turning the knob 1 – 2 turns counter clockwise and reconnected by turning it back clockwise. Removing the knob for complete makes it work as an anti theft device. Tested and recommended by the famous german classic car & motor cycle magazine OLDTIMER MARKT.