Cast Iron - Hot Dip Galvanized. Surface Mounting - NEMA 3R - NEMA 4. Unit consists of box, plain cover and gasket. Stainless steel screws. Mounting lugs drilled for 1/4"bolt. Drilling, or drilling and tapping extra, Pl0 Pendant cover tapped 1/2" fits H301 and H302 extra. P15 Pendant cover tapped 3/4", fits H301 and H302 extra. P20 pendant cover, tapped 3/4", fits H303, H304, H305 extra. Tapped holes through bosses have five threads.