EFSR-GFI cover installed on two gang EFD box together with U-Line factory sealed receptacle|Factory sealed, external seals not required in most areas, arcing is safely confined to receptacle interior|Glass filled reinforced polyester insulating blocks|Energized receptacle contacts deeply recessed to reduce danger of accidental touching|Unique blade type, brass contacts exert constant pressure along entire contact surface and provide superior electrical contact|Insulators provide superior dielectric and mechanical strength and lowest arc tracking|ECP plug fits any standard non explosionproof receptacle (NEMA 5-20R, or 6-20R) as well as U-Line explosionproof receptacles|Intermateable with competitor's plugs of like configurations