As loud as electrical horns will allow I'd suggest. If you want louder, why not tow a trailer with a compressor plugged into a portable generator for a set of air horns. You'd get "Freakin Loud" then.
Only one gripe about the Stebels, the plastic body's a bit on the cheap side. I might do what Dog did and put mine under my seat. Isnt hindsight a wonderful thing ha ha
