Fenwick LT Mask Size Chart
Sizing Measurements: There are 3 important measurements when sizing a mask for your horse or pony. The distance between the eyes, the circumference toward the bottom of the cheek bone (depending upon your horse's conformation) and the length from behind the poll to the center of the face using the bottom of the cheekbones for a reference.
XSmall: ponies, weanlings
Small: yearlings, Morgans, Arabians
Medium: refined quarter horses, small thoroughbreds
Large: thoroughbreds, standardbreds
XLarge: larger heads, warmbloods
For more adjustability, the velcro closure is suggested.