The Medela replacement nipple size S has a jaw-friendly shape and is made from soft, tasteless silicone. This provides your baby with a pleasant and natural feeling while sucking. The Medela replacement nipple fits all Medela baby bottles as well as most standard commercial bottles. Suitable for ages 0-3 months. Package includes: 2 Medela bottle nipples (silicone, size S, slow flow, for breast milk, tea, and water).