Kwikon slab boxes are engineered tough and completely concrete-tight. No more stuffing boxes with paper to keep concrete out. Made of non-metallic, non-conductive and non-corroding PVC, these fittings are durable, lightweight and highly engineered perfect for the tough poured wall environment. Residential (Low or High Rise) Commercial (Low or High rise) Institutional (Prisons Schools Universities) Hospitals and Nursing Homes (only in nonpatient care areas) Stadiums and Arenas Approved for use in non-combustible 2 hour and 4 hour fire-rated/ceiling assemblies Easily connects with Kwikon ENT Completely concrete-tight Non-metallic/non-conducting/non-corroding Supports ceiling fans up to 35 lbs. and luminaires up to 50 lbs. Fully assembled one piece unit All molded connectors have 360° locking tabs that exceed UL and CSA requirements for pull-out.