The Neno breast pump funnel is a completely safe, BPA-free product and suitable for every mum, no matter what type of birth. Neno offers 3 sizes of funnel - Slim (21mm), Medium (24mm) and Large (27mm). You can read about how to properly size the funnel to your nipple size below - in the product description.The product is compatible with all Neno brand bottle breast pumps.