Vixen Horns Loud 135dB 3/Triple Black Trumpet Train Air Horn with 1 Gallon Tank and 150 PSI Compressor Full/Complete Onboard System/Kit VXO8210/3311B Triple Trumpet Train Air Horn Tank Capacity: 1 Gallon (3 liter) 12 volt 150 PSI Compressor Thermal Overload Protection Mounting Hardware Included