Tripp Lite's instant-read CT120 circuit tester detects wiring stability in standard 120 volt AC wall sockets. Simply plug the circuit tester into a receptacle and view the lighted 3 lamp status display for verification of correct wiring, open ground, open neutral, open hot, hot-ground reversal and hot-neutral reversal fault conditions. Sticker on the tester offers lighting combinations for each wiring condition. Ultra-portable design and easy to read lighted display makes the CT120 an excellent addition to any laptop carrying case, tool belt or workbench. Low cost design saves the expense of hiring an electrician to determine wiring stability.