Anello sciolto punta cavallo serpente ferro dolce con losanga in rame (venditore britannico, p&p gratis)

Loose Ring Sweet Iron Snaffle Bit with Copper Lozenge. The added benefit of a copper lozenge gives a warm feel in the mouth and reduces the nutcracker effect of this bit. The Sweet Iron bit will develop a thin layer of orange/brown rust on the mouthpiece when temporarily not in use.

eBay