Leviton 7899-C0T NEMA 5-20R Cheetah Feed Through Receptacle with LED Indicator Light, Light Almond Mechanical shutter mechanism prevents access to contacts unless a two-pronged plug is inserted Cover made from impact-resistant nylon for longer life The SmartLockPRO receptacle automatically tests the GFCI every time the RESET button is pushed Shutter mechanism inside the receptacle blocks access to the contacts unless a two prong plug is inserted SmartLockPRO diagnoses line-load reversal upon installation as it will not reset if mis-wired