COMPATIBLE MODELS - PumpMom flange adapter for Spectra backflow protectors allow Spectra S1,S2 and 9 pump to use with most Medela Breastshield and Medela Personfit connector. Will NOT work with Medela Freestyle and Swing-Maxi Pumps. | Life Saver - Using PumpMom flange adapter to connect Medela flanges, valves, membranes, bottles with Spectra pump. A must have if you use Spectra and Medela pumping parts. | Easy to Use- Only you need to do is plug the backflow adapter into Medela pump parts, attach the Spectra hose/backflow protector to the adapter. | SAFE MATERIAL -Made with Food Grade Polypropylene(PP), BPA/DEHP Free and can be sanitized with boiling water or water steam. | 100% MONEY BACK GUARANTEE - If you experience any issues we offer a complete No Questions Asked Money Back Guarantee.