Tube & Valve System reduces air in milk Closer to Nature added comfort bottles provide optimum venting during feeding via a unique tube and valve system. Air Wide neck nipple for easy latch on The Added Comfort nipple with wide neck design allows for an easy and more natural latch on for your baby Revolutionary soft silicone nipple developed with breastfeeding experts and Moms, feels like skin and gently elongates and flexes during feeding to mimic a natural breastfeeding action. 3 way Compact Shape The compact shape of Closer to Nature bottles allows baby to feed in a natural position and to be closer to Mum or Dad. Easy to Clean & Use Closer to Nature bottles and teats are easy to clean and fill. They are microwave and dishwasher safe, yet light and easy to hold.