Nice thick plastic bottle does not buckle. The true value of this bottle is in the screw on nipple which has an anti-vacuum air vent molded in. The design is excellent and does not allow milk to pour out and into the calf's nostrils. The ring and nipple are sturdy enough an older calf will not suck it right off the bottle. I have used a lot of different bottles over the years and although I was slightly shocked at the price of this one I have to say it is worth every cent

Bought two of these last week for our new bottle calves. Didnt test the ring in the store and just assumed they would screw tight. They did not. Took the gamble, tightening it just tight enough before it skips the thread, to feed the calves their first milk replacer. After a jolt from a calf, the top popped off and lost 1/2 the milk. Next day we went back and bought two of the bottles shaped like an old coke bottle. Wow! Those tighten perfectly and had zero problems. Don't buy these. Buy the coke bottle shaped ones. I'll probably use these to feed scratch to the chickens.