Maymom Membrane for Spectra Backflow Protector is a silicone membrane Maymom backflow protector (both short and long stem) and compatible with Spectra S1/S2/ 9 Plus/ Synergy Gold/Dual Compact/S1 Pro backflow protector. Change the silicone diaphragms regularly to optimize the performance of your breastpump. Stronger material for improved performance Does NOT fit the old version of Spectra backflow protector (See images for details) Comply with EU and USA FDA regulations for materials that contact food. Tested by independent labs for quality and safety. Can be cleaned with boiling water or water steam. This product contains 8pcs of membranes for backflow protector only.