ProBlaster chrome dual truck air horns with all-metal trumpets 16.75 in. And 14.5 in. Think fire truck or ambulance horn but LOUDER! Flat mounting design allows for easy mounting behind the grille, engine compartment, or on frame rails. Includes an easy-to-fit, 120 PSI, 0.5 gallon air system. ProBlaster complete chrome compact dual air horn package with 120 PSI sealed air system. Features Model 102 compact dual air horn;0.5 gallon air tank (Five 1/4 NPT ports), all steel construction;120 PSI rated system; Sealed air compressor; All hardware included Universal.