Compatible Pumps: Replacement duckbill valves to Spectra pump parts and Selected Medela pump Parts. Compatible with Spectra S2, S1, 9 Plus, Dew 350 and Gold; Compatible with Medela breastpumps old Pump in Style (but not Pump in Style with maxflow), Swing (but not Swing Maxi); Not compatible with Freestyle, Sonata, Swing-max, PIS Maxflow. Same Suction as the Original: Maymom duckbill valves are made to provide the same suction power as the Original Spectra duckbill valves. It is recommended to replace the breastpump duckbill valve every 3-6 months or when you see a large gap at the tip. Easy to Attach and Detach: Maymom 2nd Generation uniquely designed duckbill valve has an easy grab / pull tab that you can attach/detach the duckbill valve onto/from the flange easily. US FDA listed Medical Device: Maymom products are made in compliance with US FDA Medical Device regulations with device number: D192499 Material: Made of food-contact grade silicone. BPA/DEHP free, comply with EU and US regulations for materials that contact food. Please note: This is an aftermarket product produced by Maymom. Maymom 2nd Generation Pump Valves for Spectra Pump