Reduced height design saves on valuable rack space. Center mount design is ideal for single sided racks, mount to either front or back channel face. Mounting hardware not included. 19"W version holds equipment up to 17.25" W x 15.82"D (438.2 mm x 401.8 mm), 23"W version holds equipment up to 21.25"W x 15.82"D (539.8 mm x 401.8 mm). Made of strong, lightweight aluminum; supports up to 40 lb (18.1 kg).