Maymom flange, not spectra flange or spectra USA product. It will NOT fit every mother. See picture (size chart) for details. Contains 2x 17mm widemouth flanges for spectra s1 plus pump, s2 plus pump, 9 plus pump and Motiff Luna, Ameda Mya pumps. Suitable for mother with a niple diameter 15-16mm (measured AFTER a pumping session). Talk to your lactation consultant before purchase. BPA free, DEHP free; Complies with US FDA regulation for plastics that contact foods. Compatible with spectra wide mouth bottles, AVENT 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. Dishwasher toprack safe; Steam safe for clean. Maymom Wide Neck Pump Part for spectra S1/S2 Pumps; Incl Wide Mouth Flange; Not Original Spectra Flange; Replaces Spectra Shield (17 mm Two Flanges)