CONTENTS: 6x duckbill valve and 4 x silicone membrane. Maymom replacement pump parts compatible with spectra duckbill valve and spectra silicone membrane. Not Original Spectra S2 Replacement Parts. Not Original Spectra S2 PLUS, or Spectra S1 PLUS, Spectra S3 Parts. | COMPATIBLE with Spectra S1 Spectra S2 Spectra 9 Plus breast pump (The duckbill valves also compatible with Spectra Dew 350). See photo illustrations for compatible breastpumps. Not original Spectra S1 accessories, Spectra S2 accessories, Spectra Duckbill Valves, Spectra Membranes. | SAME SUCTION POWER AS OEM VALVES. The duckbill valves are compatible with Spectra Flange and Maymom flange. The silicone membranes are compatible with Maymom backflow protector (Long, Short and Medium) and Spectra S1 backflow protectors, Spectra S2 backflow protector. Also suitable for Ameda Mya pumps. It does not fit the old version of spectra backflow protector; see photo for details. | OPTIMIZE PUMP PERFORMANCE. Replace silicone membrane, duckbill valve regularly to optimize the performance of your breastpump. Parts available in white, pink, blue, orange to match diffrent colors of your pump. | BPA/DEHP FREE. IN RETAIL PACK.; Comply with EU and USA FDA regulations for materials that contact food. Tested by independent labs for quality and safety. All items packaged in retail pack, sealed by manufacturer Maymom. Can be cleaned with boiling water or water steam.