Extech PRT200 Phase Rotation Tester

75 to 1000VAC input voltage with a 45 to 65Hz frequency range LEDs indicate phase orientation (clockwise or counter-clockwise) and whether each phase is live Beeper sounds intermittently when correct phase is detected and continuously if phase is reversed Durable housing with back cover magnet for attachment to an AC distribution panel for easy measurement Adjustable Hi/Lo LED brightness switch for making measurements in dimly lit areas or sunlight