The Lew Electric 532-SMB is a round cast iron concrete floor box with a brass top. The box is fully adjustable and offers 2 1/8" of pre-pour adjustment, and 1/2" of adjustability after it is installed. The box is deep offering 4 1/8" of height for installation, and 57 cubic inches of interior space. There are four 3/4" knockouts, 5 1/2" knockouts, and 2 1" knockouts on the sides of the box to run your wires to. The box ships with a protective cement cap to keep the box clean and safe during concrete pouring. The box does not ship with a cover, there are several options available that are sold separately. If the box is to be used in a carpeted area a sold separately carpet flange can be ordered, the CF-1100 series carpet flange adds 3/8" of height to accommodate the carpet and padding. For tile applications no flange is needed, simply pour your concrete to the level of the tile frame less the thickness of the tile. The box is UL listed for the USA, and cUL listed for Canada installations.