Features and Benefits:Tests both 12 and 24V DC;A Simple Relay Tester That Will EasilyAnd Quickly Test Most 12 And 24 Volt DCAutomotive Relays.Tests relays by simply clipping the test leads onto the relayterminal pins using a 12 or 24v DC power source. Tests awide range of 4 and 5 pin relays. Including shielded, nonshielded,relays with different pin sizes and 4 pin normallyclosed relays that other testers may incorrectly show fail.Automatically determines the relay configuration so thefully insulated gator clips can be connected in any order.Eliminates guesswork because you don?t need to connect tospecific pins, like other testers. 45" power leads with heavydutygator clips provide a secure connection to the powersource.