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.