Propane and Map-Pro™ cylinders have a CGA 600 valve with 1.000 20 UNEF RH EXT thread. Oxygen cylinders have a CGA 601 valve with left-hand threads. Main valve housing is available with nickel plating upon request. Cylinders are designed to meet title 49 CFR DOT specification 39 primarily for containing liquefied gas. Can be used to contain ether mixtures, medical gases, inert gases and a variety of calibration gases.