Switch easily between breast and bottle… and back again: Our glass baby bottles feature soft, wide-based bottle teats that are extra-stretchy and support a smooth transition between bottle feeding and breastfeeding, clinically proven to reduce nipple confusion. Known as the ‘teat babies take’: Lansinoh teat are crafted from soft silicone with a gradual slope and wide, textured base to support a 'just-right' latch and preserve the wave-like tongue movements babies use during breastfeeding. Our glass bottles fit all 4 sizes of NaturalWave teats (M size already included). Anti colic baby bottles : The Air Ventilation System features an anti-colic air vent that reduces the intake of air, helping to reduce potential causes of wind and discomfort. BPA & BPS-free: Made from food-grade, heat and thermal shock-resistant material, the glass bottle contains only 4 parts, making them easy to clean and dishwasher safe. Pump, store & feed: Lansinoh bottles are designed for compatibility with Lansinoh breast pumps, which means you can pump directly into the bottle to store milk and feed your baby without having to transfer precious breast milk.