As a mom who has been using the Spectra S2 pump for 10 months now, I was curious to try out the Maymom Duckbill Valves. Initially, I was hesitant as these valves are not the original Spectra parts. However, to my surprise, these valves have proven to be a reliable accessory for my pumping needs. Firstly, the Maymom valves are compatible with various Spectra models, including S1, S2, 9 Plus, and Dew 350. The installation process is hassle-free, and I haven't faced any issues with them falling offSee full review