The OptiFit Set and Promise provides the solution to your endless flange sizing madness, giving you the "Optimal" fit every time! What's so unique about this set is the angled shape of the flange, designed to fit your natural shape while allowing you to lean back and relax while pumping. We've also taken into account the natural fluctuations that can occur throughout a breastfeeding journey. If one or both breasts ever become uncomfortable with a flange size that used to work well, even for a day — you'll already have what you need to ensure better flow and reduced irritation. All Pumpin' Pal flanges are made in the USA from USA sourced BPA free silicone and polypropylene.  Note: X-Small and Small flanges are silicone, the Medium flange is rigid polypropylene. For additional peace of mind, our OptiFit Angled Flange Set includes The Pumpin' Pal OptiFit Promise*. The OptiFit Set of Pumpin' Pal Flanges may: Eliminate constriction of milk ducts caused by traditional straight flanges. Promote better flow and reduces irritation to the nipple area. Allow users to sit back in a more comfortable, natural position while pumping. Help prevent constriction of elastic breast tissue with Elast+Assist Technology™ (EAT). Be used with hands-free systems for the ultimate relaxed and productive pumping. Be especially effective for new moms and C-section moms. Aid in the prevention of mastitis and other breast infections caused by clogged ducts. Why Three Sizes?  Mainly, we don’t know which size is going to be optimal for your left and optimal for your right, until you try them all. Also, throughout a pumping journey, the size and elasticity of either one or both breasts can vary. What many pumping parents find is that having all three sizes provides immediate support for the natural variations that can occur throughout a pumping journey. For additional information, check out "Why Buy a Set?" below! What If I Have Larger Breasts? Our flanges take into account the elasticity of the skin, a more important indicator of fit than size of the breast.   If the sizes that come in the OptiFit Set are not large enough for you after you try them, we will send the larger sizes immediately at no cost to you. Do I Need An Adapter? Find out by selecting your pump below! As always, if you have any questions, just contact us. We're here for you! Please note, Pumpin' Pal flanges do not fit into wearable cups. *The OptiFit Set Promise is not applicable to international orders. See The OptiFit Set Promise terms & conditions.