Let me tell you, as someone who's tried multiple flange inserts, these 20mm ones are game-changers. The moment I popped them into my Momcozy M5, it was like my pump finally understood my body. No more awkward rubbing or that 'squeezed sausage' feeling some flanges give.

The food-grade silicone is SO much gentler than hard plastic flanges. I can actually lean back while pumping now without wincing - huge when you're stuck pumping during work Zoom calls. They create perfect suction too - noticed about 0.5oz more output per session compared to my original parts.

Pro tip from experience: If your Spectra/Medela feels 'off', try these before buying new flanges entirely. Saved me $40 when they fit my Spectra S1 perfectly (though heads up - there's a tiny gap with Momcozy pumps that doesn't affect performance).

Washing is stupid easy - just toss them in the sterilizer with my bottles. After 3 months of daily use, they're holding up better than the OEM parts that came with my pumps. Though fair warning: if you have very elastic tissue, maybe size up as they grip firmly.

The multipack is genius for figuring out your Goldilocks size ('this one's too big... this one's just right'). My left nipple needed a different size postpartum week 6 - having options prevented so much pain and kept my supply steady.