Extension Ring Box Type Square Number of Gangs 2 Bracket Type - Capacity 22.5 cu in Material Galvanized Steel Number of 1/2 in Back Knockouts 0 Number of 1/2 in Side Knockouts 0 Clamp Type - 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