1、Simple Operation: We only need to connect the well insulated auxiliary clips included in the unit to the 3 phase circuit under test then the unit will indicate the presence of a phase break and phase sequence via LEDs and a buzzer. 2、Accurate Detection: The phase indicator checks for the presence of both open phase and phase sequence by means of a designated LED and an audible buzzer. This handheld instrument correctly identifies the rotating field of a 3 phase system. 3、Limit Time For Continuous Use: 200V AC up to 60 minites, 600V AC up to 4 minites. Maximum Withstand Voltage is 2000V per minute (impulse voltage 4000V) 4、Measurement Frequency Range: The phase sequence tester has a defined frequency range of 20Hz to 400Hz and this making the outcome more accurate. 5、Battery Free Design: No need to charge when using. Energy saving and environmental protection. This phase indicator will not lead to pollution. 6、Anti Electric Shock Protection Clip: This product is equipped with 3 protective clips to prevent users from being electrocuted by accidental touch during measurement.