Green Guard Horse MuzzleGreen Guard Horse Muzzle The Green Guard has 50% more breathing room than a traditional muzzle, great for horses with heaves. It has an open design is cooler, lighter weight and more comfortable than other horse muzzles. Other perks of the Green Guard: Does not absorb moisture or bacteria Made from 100% food grade, non toxic material Can attach to a variety of halters You can can purchase a muzzle insert to restrict grass intake further if necessary.