Air Horn sounding like a MAC truck?

[HauntedDeadEnd]

Does anyone know a good site to find an airhorn that sounds like a mac truck for a halloween scare? Thanks

[Dark Attraction]

These might work? I don't know how good they sound, but they are cheap, and there is probably a store near you.

http://www.harborfreight.com/catalogsearch/result?q=air+horn

[FrightProps]

FrightProps has a couple of different type horns in this category that are self-contained and ready to go. Train Horns and the Psycho Blaster. Check them out. (http://www.frightprops.com/air-electric-props/airpowerednoise.html)