Features: 1.3 Ports: This half gallon gas tank has 3 ports, 2 1/4in NPT ports on the right side of the tank and 1 1/4in NPT ports on the bottom. 2.Wide Application: This air tank with 3 ports supports air pressure up to 115 PSI, universal for truck, car, train, yacht, RV, SUV system. 3.Multi Purposes: Air tank kit can be used with air horns that require on board air systems and many other air suspension applications. 4.Premium Material: The air tank is constructed of welded steel and coated with a protective film for maximum protection and durability. 5.Package Contents: This train horn tank kit includes air tank, pressure switch, air gauge, fittings, hose, thread sealant and mounting hardware. Specification: Item Type: Air Horn Tank Kit Material: Metal Maximum Working Pressure: 150 PSI Gas Tank Capacity: 2L (0.5GAL) Pressure Switch: 90psi On, 120psi Off Applicable Models: Universal for truck, car, train, yacht system.