PORCELAIN CEILING RECEPTACLE LAMPHOLDERS - Meets all UL 496 requirements. High strength insulator porcelain. Mounts on 4 outlet boxes with breakout for 3 1/4 box mounting.Pull chain socket interiors are removable . Pull chain devices include ball chain 3 ft. of cord, connector and end bell. Top wire versions have terminal screws backed out-ready for wiring- Sockets available in two piece version to permit interior replacement, dust ring protects against plaster and dirt. Shade grooves provided on two piece version.