WirthCo Battery Doctor Top Mount Compact Battery Switch without Fused Bypass is easy to install on a negative battery post. It is designed to be disconnected by unscrewing the knob a few turns, then reconnected by tightening the knob. The knob can be removed completely to deter theft and the compact size fits most battery compartments. This switch is rated 500 amperes surge and 125 amperes continuous at 12 Volts. For over 30 years, WirthCo has been a prime manufacturer of practical products for making life easier safer. California Prop 65 - Warning, This product contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.