Here's another horn option that's popular with the dual sport crowd. Loud as heck and small too:

http://adventurersworkshop.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Stebel_Air_Horns

Scroll down to the bottom for the really small version.


Todd Richmond Grapevine, TX USA '78 R80 /7 '06 FJR1300A