Corner uprights: 0.100″ extruded aluminum with angular keyhole slots 2 1/2″ apart to accept slides. Top and bottom: 0.090″ aluminum, welded to corner uprights. Reinforcing channel: 1″ x 2″ aluminum, at middle of height, welded between uprights for added rigidity. Slides: Extruded aluminum universal angle with shoulder rivet. Each pair will hold either one of the following: one 18″ x 26″ tray or pan; one 15″ x 20″ tray; one 20″ x 20″ cup or glass rack; two 12″ x 20″ pans; two 14″ x 18″ bussing boxes; two 14″ x 18″ pans (samples required). Slides are adjustable on 2 1/2″ centers. Casters: 5″ diameter NSF-approved, non-marking rubber tired wheels on swivel plate casters. Shipped assembled.