Bests & Worsts Reviews from Amazon

These bottles and nipple shape are well liked by our son, but there seems to be a manufacturing defect in the valve system. We purchased a total of 7 bottles for my child (4 from Amazon, and 3 from Babies'R'Us) all within the last two months. The cap at the end of the air tube should have a small slit cut at the very end. 5 out of the 7 bottles we purchased did not have the proper air slits cut. I fixed the situation by using a small pen knife to cut the plastic at the end. What clued me in to this problem was the fact that the nipple was collapsing on a few of our bottles - something that should not happen with a properly functioning air slit. Obviously this is a rather serious defect, given that the air valve is a major selling point of the Sensitive Tummy line (which they charge a premium for). Hopefully this was a small glitch in production, but this is extremely poor quality control on the part of the manufacturer. *I've posted two shots in the product photos illustrating the simple fix if you are experiencing the same defect as we were. http://www.amazon.com/gp/customer-media/permalink/moP836WFH229I0/B004KBLDHO/ref=cm_ciu_images_pl_link http://www.amazon.com/gp/customer-media/permalink/mo3NA14OB6KRMZ3/B004KBLDHO/ref=cm_ciu_images_pl_link