Vixen Horns Loud 149dB 4/Quad Chrome Trumpet Train Air Horn with 1.5 Gallon Tank and 150 PSI Compressor Full/Complete Onboard System/Kit VXO8530/4114 Quad Trumpet Train Air Horn Tank Capacity: 1.5 Gallon (6 liter) 12 volt 150 PSI Compressor Thermal Overload Protection Mounting Hardware Included