Philips Avent Natural 4oz Bottle is the most natural way to bottle feed. The wide breast-shaped nipple on the Natural bottle promotes natural latch-on so you can easily combine breastfeeding and bottle feeding. The ultra soft nipple mimics the feel of the breast. Our flexible spiral design combined with the comfort petals allow for a natural movement while baby feeds. The bottles have unique Airflex vent technology integrated into the nipple and are designed to reduce colic and discomfort by venting air away from your baby's tummy. 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. The Natural bottle is made from polypropylene, a BPA free material, and works with all nipples and caps from the Natural line.