Electrical Box, Box Type Masonry, Number of Gangs 2, Bracket Type -, Capacity 45 cu in, Material Galvanized Zinc, Number of 1/2 In. Back Knockouts 4, Number of 1/2 In. Side Knockouts 12, Clamp Type -, Number of 3/4 In. Back Knockouts 4, Number of 3/4 In. Side Knockouts 12, Nominal Depth 3 1/2 in, Nominal Length 3 3/4 in, Nominal Width 3 25/32 in, Color Silver, Standards File E195978, UL 514-A Listed