The Triplett ET102 is a useful and necessary tool for residential and commercial electricians, home inspectors, and DIYs. You can detect faulty wiring in 3-wire receptacles. Lights display 5 wiring faults: Open Ground, Open Neutral, Hot/Ground Reverse, Open Hot, Hot/Neutral Reverse with an easy to read fault label on both sides for receptacles with ground up or ground down installation. Unique "Loop Design" allows for easier removal when testing is complete. cULus Listed. Founded in 1904, U.S.-based Triplett Test Equipment continues to be on the leading edge of specialized testers. Whether supplying vital test equipment to the U.S. Signal Corps during WWII, or providing the railroad industry with essential testers to ensure the safety of their crews and the public, Triplett prides itself on developing innovative, reliable, and durable test equipment that also won't break the bank. Triplett's catalog contains a wide array of test equipment parts and accessories such as multimeters, voltmeters, cable testers, security cameras and security camera accessories, wire cable mapping kits, video monitors, and other specialty testers. They serve industries such as HVAC, security, electronics and electrical, telecom, and more.