Chicco Duo

FWIW, my Chicco duos don't fit on my knockoff Spectra flanges. They look and feel like they should, but they don't quite screw on. Maybe they work with OG Spectra flanges though? I'm pumping into either glass bottles or Boon Nursh bottles. The glass ones are Matyz and need a gasket to stay screwed on securely, which is annoying to wash. The Boon Nursh bottles needed a special adapter. There do seem to be quite a few adapters out there for different bottle types though, if you have a different ...