3 PRONG PLUG COVER (NEMA-5) - Specially designed to help shield North American 2- & 3-prong plugs from damage, weather, and wear. Perfect for labs, contractors, and more! EXTENDED LIFETIME - The extension cord plug cover has an innovative design that helps save money by protecting cords & eliminating the need for frequent replacements. CRUSH-PROOF GUARD - Each outdoor plug protector has a durable rubber casing that helps safeguard prongs, even in demanding environments. MULTI-USE VERSATILITY - These power cord protector caps can be used to protect heater blocks, trickle chargers, extension cords, power tools, and more (any piece of equipment that has a standard 120V US Plug). SNAP & SECURE - The electrical plug cover has been designed for hassle-free use with all standard 2- and 3-prong 120V plugs. Enjoy lasting protection without compatibility worries.