BornFree leak proof BPA-Free baby bottles feature an innovative venting system designed to promote Active Feeding and and help minimize the painful symptoms of colic. Pack contains 1 BornFree venting system for use with all three bottles Each bottle comes with a level 1 nipple and a cover.3 9oz glass bottles, 3 Level 1 nipples, 1 BornFree venting system, 1 Voucher for 2 venting systems. and they are uniquely suited for breastfed babies who are being introduced to bottle feeding. The air valve begins a steady flow of liquid once baby has started to nurse just like with breastfeeding.