Hospital grade, extra heavy-duty four-in-one. Terminal wiring screws fit inside a standard single gang wall box; adapter plate not required (optional). Impact resistant nylon cover and base for strength and resistance to chemicals and corrosives. Easy-to-read voltage and amperage rating molded onto face. Extra heavy-duty, T-type triple-wipe bronze contacts for maximum performance. Ground holes configured up or down to be outside the device, accommodating up to 4 Fed Spec size straight or angled plugs. No.8 terminal screws accept up to No.12 solid or stranded copper wire. Termination anchor holes for easy conductor wiring. Exclusive shield-wall design protects ground connection from contact with live circuit conductors. A and B molded on face and back for easy identification of receptacle pairs for split-circuit conversion. Convenient built-in strip-gauge. Backed by a limited 10-year warranty. NEMA type 5-20R.