Electrical Box, Box Type Square, Number of Gangs 2, Bracket Type -, Capacity 21 cu in, Material Galvanized Steel, Number of 1/2 In. Back Knockouts 1, Number of 1/2 In. Side Knockouts 0, Clamp Type -, Number of 3/4 In. Back Knockouts 4, Number of 3/4 In. Side Knockouts 8, Nominal Depth 1 1/2 in, Nominal Length 4 in, Nominal Width 4 in, Color Silver, Standards UL