The Extech PRT200 is a non-contact phase sequence tester with an input voltage of 75-1000 VAC and a frequency range of 45-65 Hz. This tester has LEDs that indicate whether each phase is live and its orientation; a beeper sounds occasionally when the right phase is detected and continually if the phase is reversed. An adjustable Hi/Lo LED brightness switch allows you to take measures in low-light or direct sunshine, and the CAT IV 600 Volt safety certification and fully-insulated, wide-jaw alligator clips make it suitable for industrial applications. The PRT200 comes with a one-year guarantee and three built-in 30 in. The test leads include huge color-coded alligator clips, 4 AA batteries, and a bag case.