Kleinn Air Horns 101 Black Dual Air Horn Dual features a sleek, black finish. The trumpets are 10- inches and 7.25- inches in length. The compact design and black finish allow for a discreet installation. This dual horn system has an all XCR 2.0 black coated body with black zinc alloy trumpets and requires an onboard air system up to 150-PSI for operation (not included). There is a Vortex 4 ?12-volt electronic air horn solenoid included. Too Loud? Too Bad.