Easy Latch On: Unique skirt on the nipple flexes to your baby's feeding rhythm. Milk will only flow at the pace chosen by your baby for more comfort. Ergonomic shape: Due to the unique shape, the bottle is easy to hold and grip in any direction for maximum comfort, even for baby's tiny hands. Compatible with the majority of the Philips Avent range. Significantly reduces fussing made of BPA free material (polypropylene) Simple to use and clean Fit you baby's growing needs Anti-colic valve: Two piece anti-colic system Size: 4 oz. Color: Clear. Gender: Unisex.