About the Product: 2 BACKFLOW PROTECTORS Use with SPECTRA S1, SPECTRA S2, SPECTRA 9PLUS Breastpump. Replacement for Spectra pump Duckbill Valves. Including 2 Large Cases, 2 Small Cases, and 2 Silicone Diaphragms. Replacement for Spectra Backflow Protectors.NOT ORIGINAL SPECTRA PARTS. CLOSED SYSTEM.