These items are after market parts made by Maymom to replace your Ameda Flange and Ameda white valve/duckbill. It is well known that choosing the correct size of flange (breastshield) is important to achieve comfortable breastmilk pumping. While Ameda provide CustomFit flanges, some of the sizes are achieved using inserts which are not easy to use, and tend to leak air easily. Maymom's flange is one-piece design to achieve the size you want. Because it is one-piece, so no leaking air and easier to use. For some models of flanges, Maymom also offer customers a choice of either duckbills or Medela type of yellow valve/membrane system for the system to work. Customers' experiences show that the duckbill system is easier to use while valve/membrane systems lasts longer. It is your choice! Most importantly, Maymom stands behind the quality of her products. Customer service/satisfaction is her Job #1 after the sale. Buy Maymom's product with confidence.