Vintage Campanelclax bicycle bell horn! Very old and very cool, Very rarely seen for sale. Sounds like a toad! Very unique.
You'd be the only one around with one of these & would look amazing on that vintage classic bicycle!
http://www.ebay.co.uk/itm/VINTAGE-CAMPANELCLAX-CLAXTON-BICYCLE-HORN-/?nma=true&si=bewo%252FPv4WrBxugDuboNQBXdtw3o%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557