Flexible Filly Slow Feed Grazing Muzzle by Thinline Thinline rethought the design to be softer, lighter and less confining. Constructed of a pliable material that reduces the chances of the muzzle getting snagged, it is also soft on equine teeth and lips. The Flexible Filly Slow Feeder Muzzle is well-ventilated and safe, rated to break just before your leather turnout halter Available in three sizes. There is so much flexibility in this horse grazing muzzle it will fit a variety of horses. For horse sizing. If a regular horse halter fits when taken all the way up, order the smaller version. If a horse size halter fits at the last hole or two, order the larger size. If you are on the fence, always order DOWN to the smaller size. The Flexible Filly slow feed muzzle is a horse grazing muzzle designed for comfort and breathability. Flexible enough for horses to enjoy turnout time. Mini-Pony. Larger Miniature horses and up to large pony. Center Grazing hole is = 3cm, 1.2 inches Cob-Horse. Cob, Arabian, Quarter Horse or Horses on the smaller side. Center grazing hole is 3.6cm, 1.44 inches-Restrictive Grazing hole is 2 cm Oversize-Draft. Larger horses, Draft, Warmblood and Oversize. Center grazing hole is 3.6cm, 1.44 inches, Restrictive Grazing hole is 2 cm