ITEM NAME:Car Auto DC 12V Volt 30/40A Automotive 4 Pin 4 Wire Relay&Socket 30amp/40amS Gw.Rated current: 40A. 1X Relay Socket. Relay harness length: approx. 12 Volt 30/40 amp 4-prong relays. and sockets are used for many car electronic applications to turn. Currents property: DC. amperage such as car alarms, remote starts, fog lights, stereos, fans.