Maymom flange, not spectra flange or spectra USA product. It will not fit every mother. See below for details. Contains 2x 21mm widemouth flange and 2nd Gen. Valve for spectra s1 plus pump, s2 plus pump, 9 plus pump and Motiff Luna, Ameda Mya pumps. Suitable for mother with a niple diameter less than 19-20mm (measured AFTER a pumping session). Compatible with spectra wide mouth bottles, AVEN bottles, and Maymom wide mouth bottles. They are NOT compatible with OTHER wide mouth bottles. Made by Maymom, not original spectra company. Maymom is not affiliated with Uzinmedicare, the trademark owner of spectra. BPA free; Complies with US FDA regulation for plastics that contact food. Dishwasher top-rack safe; Steam safe cleaning Maymom flange and valve compatible with spectra pump s1, s2 and synergy gold. also compatible with ameda mya and mya pro.