Sterile PVC Sterile Guard Protector is used as a protective cover of A.I. guns. It prevents the transfer of contaminants into the uterus during insemination or embryo transfer. A slight forward push advances the gun or tube through the protective tip. The small diameter version (0.212� I.D., 0.255� O.D.) is designed for use with most straw guns, spiral or ‘O’-ring styles. The larger diameter version (0.24� I.D., 0.3� O.D.) is designed for use with the disposable straw guns and infusion tubes.