Standard Single-Sided Steel Shelf Economical rack or wall-mounted shelf for miscellaneous equipment. Made of cold-rolled steel and may be rack or wall-mounted. 19” rack-mountable, holds equipment up to 17.25”W x 14.75”D (438.2 mm x 374.7 mm). Supports up to 35 lb (15.9 kg). Standard Double-Sided Steel Shelf An economical rack or wall-mounted shelf with twice the shelf space for centered loading and deeper equipment handling. Made of cold-rolled steel, this shelf mounts on double-sided racks only. 19”W rack-mountable, holds equipment up to 17.25”W x 21.50”D (438.2 mm x 546.1 mm) and supports up to 25 lb (11.3 kg) per side or 50 lb (22.7 kg) total.