Professionals Choice Bob Avila Medium Port with Roller.
This bit features a medium port and copper roller that works off bar and palate pressure. The mouthpiece offers moderate tongue relief. Good for working with older, more mature horses. This bit requires light contact.
Port: 2 1/2", Mouth: 5", Cheek: 8"
NOTE: This bit will rust when exposed to moisture. This creates a sweet taste in the horse's mouth and promotes salivation. - See more at: http://profchoice.com/i-7196088-bob-avila-medium-port-with-roller-bit.html#sthash.XPrAaZiR.dpuf