Vixen Horns Loud 149dB 4/Quad Black Trumpet Train Air Horn with 1.5 Gallon Tank and 150 PSI Compressor Full/Complete Onboard System/Kit VXO8115/4124B Immensely loud Quad Trumpet Train Air Horn Tank Capacity: 1.5 Gallon (6 liter) 150 PSI Compressor (12 volt) Thermal Overload Protection Mounting Hardware Included