The Triplett PR400 determines correct phase wiring sequence (L1, L2, L3) for 3-phase system installations. Color-coded test leads are provided for connecting to the three mains phases of the system under test. You can view results on an easy-to-read graphical display to see phase direction (clockwise/counter-clockwise) and which phases are live. Includes test leads with large color-coded alligator clips and carrying case. No battery is required. CAT III 600V safety category. 1-year warranty.