I have to admit that once I received the bottle, I thought it was the strangest looking thing I have ever seen! The top of the nipple is completely open. I was very skeptical about how well it would work. I have to tell you though, that I wish I had a few more!
Medela Calma works is a series of valves. The nipple is composed of three pieces. The nipple is soft, rounded and completely open in the top. It seals around two areas; the base around the inner valve and around the inside edge of the inner valve. The inner valve has a small little hole inside near the middle. It fits into the outer valve. The outer valve also has a small hole in it. The inner valve has legs that slide through the outer valve and the outer valve closes around the outer edge of the nipple. These legs are where the bottle screws into. So the bottle actually attaches to the inner valve and not the outer case. These sets of valves work a lot like a breast. The baby has to suckle to get the milk to flow and then there is a 'letdown'. Milk never collects into the nipple area. Plus, saliva never mixes back into the milk in the bottle.
the Calma. I think it is her favorite. It is my favorite too because it is so easy to clean. The parts come apart so easily and there are no spots where dried milk can get stuck.
The Calma has earned The Trophy Wife's Seal of Approval!