2 NENESUPPLY COMPATIBLE BACKFLOW PROTECTORS for SPECTRA S1, SPECTRA S2, SPECTRA 9PLUS Breastpumps. Including 2 Large Cases, 2 Small Cases, and 2 Silicone Membranes, Not original Spectra s1 accessories. MADE BY NENESUPPLY. NOT ORIGINAL SPECTRA PUMP PARTS. Compatible with other Spectra S2 accessories and Spectra S1 accessories. Materials do not contain any BPA, and can be sanitized with boiling water or water steam. CLOSED SYSTEM. No contact between milk and tubing.