Bottom shelf, handles and trussed frames are chrome plated. Cylinder racks are 5/16″ (8mm) in diameter with 41/2″ x 41/2″ (114mm x 114mm) openings for gas cylinders. Racks accommodate twelve D or E cylinders and are plastisol coated. Cart design conforms to NFPA 99. Units are finished with aluminum split sleeves and four UL recognized 5″ (127mm) conductive casters.