Maymom duckbills compatible with Spectra s1, s2, Motif luna, compatible with Ameda Mya and Mya Pro. Built to last longer than other and OEM duckbills. Made by Maymom. Not original Spectra pump parts. Work with Spectra S2 accessories. Replacement to Spectra duckbill valve. SAME suction power as OEM valves. Compatible with Spectra Flange and Maymom breastshield 4 unused in original but opened package