Cashel Crusader Standard Mule Donkey Fly Mask with Ears Mule Fly Mask with Ears. Note all mule and donkey sizes have 13" ears. Rated #1 by clinicians and equine publications for comfort, design and fit Stellar protection against flies and insects Soft coated nylon micro-mesh blocks 70% of damaging UV rays Split-top opening, forelock hole keeps horses comfortable