Specially-designed nipples for Caprine-style feeders (regular and small). Nipple fits through a 5/8" hole in pail. (For metal pails which have thin walls, 9/16" hole gives snugger fit.) Flange on back of nipple holds plastic tube which extends down into the milk. Kids "drink through a straw." Nipple fits onto most pop bottles; many breeders prefer the Caprine nipples for bottle feeding.