Commercial Grade. Shallow design for maximum wiring room in box. Side wired, large-head terminal screws and back-wiring clamps accept up to No. 10 copper wire. Triple wire power contacts for maximum conductivity and plug retention. Captive mounting screws for fast installation. Convenient washer-type break-off plaster ears for best flush alignment. Break-off tabs for easy 2-circuit conversion. Heavy-gauge rust-resistant steel mounting strap.