· Shutter mechanism inside the receptacle blocks access to the contacts unless a two-prong plug is inserted, helping ensure hairpins, keys, etc., will be locked out· TR symbol on residential receptacles assures they meet the 2008 NEC requirement· Ultrasonic heavy-duty construction offers long, trouble-free service life· Heavy-gauge, rust-resistant steel mounting strap· Shallow design for maximum wiring room· Wallplate sold separately