SIZES: I measured the length of the fronts of the masks (in front of the ears at the top of the mask to the bottom of the mask) to give buyers a better idea of size. Small: 20cm in length Medium: 25cm in length Large: 28cm in length. Protects your horse's face and eyes against flies, dust, dirt, and debris! Protects your horse’s face and eyes from harmful UV rays. Aides in healing after eye injuries. See through mesh won’t obstruct your horse’s vision. Double latch closure, making it harder for other horses to pull off.