The Triplett PR600 Non-Contact Phase Rotation Tester determines the correct phase wiring sequence for 3-phase system installations. Users can clip on to insulated wires with a maximum conductor diameter of 1.3 in. (33mm). Users can view the results on an easy-to-read LED display to see phase direction (clockwise/counterclockwise) and which phases are live. A buzzer sounds to indicate live wires and clockwise (intermittent beep) or counterclockwise (continuous beep) directions. There are 2 selectable brightness levels for use in sunlight or dimly lit areas and a back cover magnet that mounts onto metal surfaces for hands-free operation. Additional features include Auto power off and Low Battery indication, and CAT IV 600V safety category.