Viking Horns V1005ATK 3 Gallon (12 Liter) Air Tank Kit For Train Air Horn Systems Tank Capacity: 3 Gallon (12 Liter) Air Storage: max 200 psi 6 ports: 4 of 1/8 inch, 2 of 1/4 inch ncludes air gauge, pressure switch, hardware, fittings, hose Tank Size: 21 inch long, 7-1/2 inch high, 6-1/2 inch in diameter