UT523 Series Earth Resistance Soil Resistivity Tester is specially designed and manufactured for measuring earth Accurate determination of phase status Portable; lightweight unit LED and audible indicators of phase status AC voltage range of 70V-600V Specifications Missing phase detection R-S or S-T light off Live power detection R-S or S-T light on Circuit break detection R-S or S-T light off Product size 70mm x 75mm x 30mm Product net weight 180g Voltage Range 70V~600V Phase sequence [Positive phase] four phase lights on clockwise, and beeping sound [Negative phase] four phase lights on anti-clockwise, and solid sound Voltage detection R-S or S-T light on Power 1.5V battery (R6) x 2 Frequency range 40Hz~70Hz