This product is made to use with these pumps: spectra s1 s2 spectra 9 plus spectra dew 350 breastpumps and all medela breastpumps except medela. It also works with NeneSupply breastshields. One duckbill valve replaces medela valve and membrane. With this valve breastfeeding moms have fewer pump parts to wash sterilize and assemble. Medela membrane is thin and small and can get lost easily. Made from pure materials and complies with eu regulations for materials that contact food. The material is silicon the same as medela membrane and spectra valve. They are safe to sterilize in water steam or boiling water.
