The First Choice teat has the special orthodontic NUK shape & an extra wide lip support to simulate breast feeding as closely as possible. The NUK Air System within the teat allows air to flow into the bottle though a vent. As the baby sucks, this ensures that no air is swallowed during feeding, thus helping to prevent colic. The NUK orthodontic shape & Air System have both been approved by the British Dental Health Foundation. Size 1 is suitable for 0-6 months & the medium feed hole is suitable for milk. Each pack contains 2 teats. NUK teats are Bisphenol A free.