Caspers Electronics HD relay kits are designed for high-current applications like high-power coolant fans, high-flow fuel pumps, or any other load switching that requires an SPDT 40 amp relay. These kits include sealed relays with sealed connectors and come with three 12/10 gauge pull to seat terminals for relay contacts, as well as two 18/16 gauge terminals for the relay coil. Installing Caspers Electronics HD relay kits is a breeze with the simple use of a crimp tool.