Frames: Frames are 1" x 2", 16-gauge (.065") cold-rolled steel tubing with 14 - gauge (.083") vertical, main members, for added strength. Frames have .250" diameter holes through 2" side of tube every 2" graduation for shelf adjustability. Each frame segment is equipped with two spreaders. Glides/Casters: Frame glides are 5/16-18 threaded stem with 1.13" diameter foot. Frame casters are 5/16-18 threaded stem with 2-7/8" diameter x .75" wide dual black nylon wheels. Shelf Supports: Shelf supports are 14-gauge (.075") H.R.P.O. steel with two .250" diameter holes on 2" centers and a support finger for rigid installation. Shelves (upper and lower): Thermally fused melamine (good two sides) over .75" thick x 44-47 lb. density particleboard core. Upper shelves are flexible PVC T-molded and lower shelves are PVC edgebanded. Shelves tested to 250 lbs. per 24" lineal without failure. Work Surfaces: Thermally fused melamine over 1.00" thick x 44-47 lb. density particleboard core with flexible PVC T - molding. Attachments: Single and dual wire keyboard holders as well as keyboard drawer attach easily to shelves. Keyboard drawer and adjustable keyboard support (19500) can be attached to the under side of work surfaces. Paint Finish: High solids polyester, baked enamel finish.