The Stop Shock II Circuit Analyzer makes it easy to test GFCI receptacles and determine the appropriate wiring correction needed. This GFCI tester uses advanced circuitry and a patent-pending proprietary design to precisely detect the required low resistance (less than 10ohms) on ground wire and provides a clear and easy-to understand single LED readout indication for Correct wiring or Bad Ground, Open Neutral, HOT/GND Reverse, HOT/NEU Reverse and Open Hot wiring errors without the need to memorize or decipher a dual-indication chart. The Stop Shock II includes a GFCI test function to test outlets wired in parallel to GFCI circuits (bathroom, kitchen and outdoor receptacles require GFCI protection). Designed for the jobsite this tester features Hi-impact ABS housing with a 250 lb crush rating and the ability to withstand drops of up to 10 feet. Backed by a lifetime warranty this tool will speed up the testing process and increase your productivity for years to come