Heavy Duty lever operated On-Off Master Battery Disconnect Switch operates on the Battery Circuit Only. Switch does Not disconnect alternator or generator circuits and vehicles with an alternator must be turned off before operating Disconnect Switch. Heavy Duty metal construction is ideal for off-road, agriculture or other wet and dirty environment conditions. Switch has 2 plated copper 3/8\" studs with brass hex head nuts, with a 3/4\" mount hole diameter and overall length of 4-3/8\". Switch in Off position helps reduce the possibility of theft or fire.