When ordering multiple tanks, please create separate orders for each tank or call us at 858.581.2800 to order, to ensure accurate shipping rates F-x Series is a DOT E-13488 specification, no overfilling is allowed. F-x Series is Transport Canada (TC) Approved. All F-X Series cylinders are oxygen cleaned and suitable for Nitrox use. Inlet Thread 3/4 - 14 NPSM. Self draining boot and DIN/Yoke valve included. Color: Grey, corrosion resistant finish for durability. Specifications: Height 20.87"(w/o valve), Diameter 7.24", Weight 28.6lbs (w/o valve) This is a very high quality tank that can last a lifetime!