its called an Airzounds. its a portable air horn. all you have to do is pump it up to 80psi with a bike pump and you get like 20 blast of loud ass horn. all sorts of people heard it at the Creatures moped rally this fucker is loud. i had it on my Tri-rad.
anyway, it still works great. it came with a handlebar mount but it was too small for a moped anyway. and i threw it away. just use a ziptie.
i paid 40$ for it. so its yours for 25$ and like 5$ shipping.
first person to send the money to my paypal gets it.