Review on Spectra S2 & S1 Breast Pump Replacement Kit - 27Mm Flange, Duckbill Valve, Backflow Protector Compatible W Nenesupply Parts. by Jody Kashani

The duckbill valves are good, and I like the flanges, but the backflow protector parts aren't quite as tight as the parts that originally came with my Spectra S2. There's an extra clicking sound with each suck and I can't pinpoint what it is. There have been a few times where I noticed milk drops on my leg or the table when I hadn't taken the flange off of me yet. I wasn't able to find a leak but again, this didn't happen with the Spectra brand accessories.