Vixen Horns 1 Gallon (3 Liter) Train/Air Horn Tank with 150 PSI Compressor Onboard System/Kit 12V VXO8210 Tank Capacity: 1 Gallon (3 liter) 12 volt 150 PSI Compressor Anti-Corrosion Coating Precision Welded Pressure Gauge, Pressure Switch, Air Hose and Mounting Hardware Included