The Stop Shock II Circuit Analyzer makes it easy for anyone to use. This GFCI tester uses advanced circuitry to provide a 1 LED readout and precisely detects the required low resistance (less than 10ohms) on ground wire - instantly. This patent pending outlet tester has a simple 1 LED readout with no dual indicators or charts to read. The Stop Shock II includes GFCI test function to test outlets wired in parallel to GFCI circuits (all bathroom, kitchen and outdoor receptacles require GFCI protection).