The Edsal UR185L-BLK five-shelf standing shelf unit has a 16-gauge steel rack and shelves made of particle board to support an 800-lb. per shelf capacity and a 4000-lb. total capacity when the weight is distributed evenly across all shelves. This unit has double-riveted beams that lock into double-rivet holes on the corner post for structural security. The corner post rivet holes on this unit are punched at 1-1/2" intervals for precise adjustment to desired shelf height. The steel rack has a black enamel finish to resist corrosion. This unit is open on all four sides to facilitate access to shelf contents from any angle.The posts on this unit have a two-piece design so it can be assembled vertically to create one 72 x 36 x 18 inch (H x W x D) unit, or assembled horizontally to create two 36 x 36 x 18 inch units, one unit with two shelves and one unit with three shelves. (H is height, the vertical distance from lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.) This shelf unit has a rivet lock design for boltless assembly. Assembly instructions are included. A rubber mallet (sold separately) is recommended for assembly.Standing shelf units are commonly used to store items to help create organized, efficient, and safer work areas. These systems typically consist of a frame or rack with open shelves. Added components such as casters, wheels, or handles are used for applications that require mobility. Standing shelf units are used in a variety of office, industrial, educational, and residential settings.Edsal Manufacturing Company manufactures storage systems and industrial furniture. The company, founded in 1952, is headquartered in Chicago, IL.