LuvLap Natura Flow Feeding Bottles are ergonomically designed to be easily held while feeding the baby. All LuvLap bottles are 100% BPA free and fully sterilizable. The teats are 100% Liquid Silicone and have an anti-colic valve that vents air into the bottle, preventing any air from entering the baby??s tummy. The teat has grooves at the tip, which encourage peristaltic suckling, while the wide base helps the baby get a natural latch, similar to that on the mother??s breast. This helps easy transition between breastfeeding & bottle feeding. The grooved teats and superior silicone quality ensure no nipple collapse, helping in an uninterrupted feed.