MPC All-in-One 12-Volt Air Compressor System Kit for Truck Horn & Train Horn 130 PSI, 1-Gallon Tank 130 PSI One-Piece Tank Compressor System (Dimensions: 20.5" L x 5.50" W x 7.5" H) 4 Liter Steel Air Tank Kit Includes A Pressure Switch (100 PSI on, 130 PSI off) and air pressure gauge Bonus Item - Free Wiring Kit Need Tech Support? We also offer Free Tech Support.