Premium Non-Contact Voltage and GFCI Receptacle Electrical Test KitGFCI Receptacle Tester features a large backlit LCD readout of voltage, and clear indication of wiring conditions LCD readout shows the time required to trip a GFCI device Patent pending detection of Open Neutral Open Ground wiring fault For use on 3 wire, North American 120V electrical outlets only Non contact voltage tester's dual range detects from 12 to 1000V AC or 70 to 1000V AC for a broad variety of low voltage or standard voltage applications