Philips AVENT SCF671/37 Natural 4 Ounce Glass Bottle is the most natural way to bottle feed. The wide, breast-shaped nipple promotes natural latch-on so you can easily combine breastfeeding and bottle feeding, and the unique comfort petals provide an extra soft, flexible nipple without nipple collapse. In addition, the anti-colic newborn-flow nipple releases air back into the bottle rather than into your baby's tummy to help newborns feed comfortably and easily. The ergonomic shape makes it comfortable for parents to hold and easy for small fingers to grasp. Assembly is simple, with only a few parts, and the wide bottle neck makes filling and cleaning easy. This Natural Philips AVENT bottle is made of premium quality borosilicate glass, a BPA free material, and is printed using organic ink and made from only virgin raw materials, to ensure the highest quality for ultimate purity. It is heat and thermal shock resistant, so it can be safely stored in the fridge, warmed and is easy to wash and sterilize. Works with all nipples and caps from the Natural line.