This Nurser prevents "gulping" and helps calves gain weight faster right from the start. The bottle, fashioned of a special plastic with pint markings, won't crack or break and lasts indefinitely. It's light and easy to clean and sterilize. The Calf Nipple is rubber with cross-cut opening for full flow and air hole which prevents vacuum. Complete Nurser include 2-quart bottle and snap-on calf nipple. Wt. 12 oz.