Most like mother #1 selling bottle system*. It is also pediatrician recommended. This system is designed to help baby switch between breast and bottle. Clinically shown reduces gas and colic In a clinical study, 8 out of 10 mothers indicated that their babies showed fewer signs of gas, colic, and other feeding discomforts Clinically shown to support baby's own natural feeding pattern and support breastfeeding Baby sucks and swallows in a coordinated rhythm that is similar to how they feed from the breast Baby breathes more naturally Baby can control the flow of milk, so he/she takes in just the right amount Pre-sterilized, disposable liners Keep air out for more comfortable feeding For a clean bottle any time 100% leak proof guarantee Pre-formed for easy one-handed assembly and clean-up Bisphenol-A Free (BPA) and Phthalate free Patented NaturaLatch nipple Clinically shown to mimic baby's latch-on like the breast Slow-flow nipple designed to replicate the natural flow of the breast, so baby takes in the right amount Compatible with the Playtex Nursing Necessities breast pumps Just pump, store, and feed using the One Step Breast Milk Storage Kit** Easy to store and freeze directly in the liner *Based on sales volume **Sold separately Made in China Baby, Children & Toys , Feeding Essentials , Breastfeeding , Bottles