The GK-500 compatibility vessel is a 4 oz. / 120cc safety coated vessel. MADE IN U.S.A. (FOR WASHABILITY ONLY). IT MUST BE SHIELDED AT ALL TIMES WHILE UNDER PRESSURE! It has an aluminum and nylon coupling that accepts a standard 1 inch aerosol can valve. Because of it's simple, yet safe design it is very affordable. The GK-500 comes with a buna gasket to be placed around the dip tube of the valve. Then placed on top of the nylon coupling and then clamped down with the aluminum male part. It is completely reusable, crimping is not needed.*Teflon gaskets are available. *NOT FOR DOT TRANSPORT!