Frame and supports: 1″ square aluminum tubing with .063″ wall. Gussets: Each frame and cross support junction shall be joined with a two-piece die-stamped aluminum gusset, riveted to frame and cross supports. Tray slides: extruded aluminum angle 1 7/16″ high x 1 7/8″ wide x 0.068″ thick. Bearing surface with two raised beads providing a minimum of friction. Slides are riveted to frame. Casters: 5″ diameter NSF-approved, non-marking rubber tired wheels, on swivel stem plated casters. Shipped knocked down factory assembly available.