Here you can find for your truck compressed air horn with very powerful sound, they are complete with spoiler.
Truck compressed air horn with spoiler, 108dB, with casing in
HK 12V 150db Air Horn Kit for Truck Car, Super Loud
12V 24V Loud 130dB 3 Pipe Triple Trumpet Train Truck Air Horn with
HK 12V 150db Air Horn, 18 Inches Chrome Zinc Single
Air horn Beam double 55/60cm stainless steel (compressed air - All
HK 12V 150db Air Train Horn Kit with Compressor Single
Air horn Beam RETRO 70cm stainlesssteel (compressed air) - All for
HK 12V 150db Air Horn Kit for Truck Car, Super Loud
CARMOCAR 12V 150DB Air Horn,Chrome Zinc Single Train
MaxLouder 150DB Air Horn with Compressor, 18 Inches
HK 12V 150db Air Train Horn Kit with Compressor Single
Truck compressed air horn with spoiler, with casing in stainless
Truck compressed air horn with spoiler, 108dB, with casing in
HK 12V 150db Air Horn, 18 Inches Chrome Zinc Single
UNO MINDA P882002PS AIR Pressure Horn(EPS) 2PIPE(24V,>108 dB