Universal Relay Buddy efficiently tests both 12 and 24 volt relays, quickly indicating whether therelay is good or bad. Its five test ports accept 7 of the most common relays in use. Universal Relay Buddy's internal circuitry sorts out the difference between SAE standard/bifurcated/two branch relays as well as that special green BMW/Mini relay with two 87 pins and pins 86/30 switched. This gives us tremendous overall testing coverage not available on previous testers. If the relay plugs into Universal Relay Buddy, there is extreme high probability, near 100%, that it will successfully test that relay.Maximum relay test coverage:All SAE standard wiring relaysIncluding bifurcated & two branch relays with two 87 pinsBMW/Mini two branch relay w/pins 86 &30 switched & two 87 pinsTest nearly any relay with 4 or 5 pinsTests both 12 & 24 volt relays!Error prompt for low/high battery supply voltage