Fits on any Springer Magrath Fluidfeeder (sold separately) to allow mouth feeding of fluids to young calves that are unable to nurse from a cow. The nipple is designed to allow liquid to leave the bottle while keeping air out. When used properly, the rate of flow is slow enough to cause the calf to form saliva freely, which is necessary for proper digestion. Nipple attaches easily to end of Fluidfeeder tube.