Top positive review
Not necessary for Spectra flanges
October 22, 2018
You might not need this product. I'm not sure about all bags, but the NUK bags will actually go on the Spectra flanges if you put the bottom of the flange into the bag at an angle and then straighten it. The bag can come off but not accidentally...it would require a hard pull (hard enough that you'd likely pull the bag off the adapter's clips too). We have Maymom flanges for the Spectra pump, and they work even better as I'm describing than the Spectra flanges. It seems they're just a little wider at the threaded area making the bag fit even more snuggly.
The product is good and works as advertised. My one complaint is I think the clips could be a little longer so it's easier to get them past the second zipper on the bag. But try this trick before wasting your money.