The SDKIT17-734 is a direct fit 100% Bolt-On onboard air and train horn system, featuring the model 730 Demon triple train horn, 3-gallon air tank and model 6450RC Heavy Duty high output waterproof air compressor. The kit can be upgraded to be even LOUDER by adding a P/N 6890 Ultra Blast Master Valve Upgrade Kit. System also includes a quick connect tire inflator with storage bag. Kleinn vehicle specific train horn kits are also available as a stand alone onboard air system without a horn.