CONTENTS: 2ct Small 21mm flanges and 2ct duckbill valves compatible with Spectra S2, Spectra S1 and Spectra S1Plus breastpump. Made by Maymom. Not Original Spectra Flanges, Spectra Duckbill Valve. Can use Maymom flange for Spectra S2 pump parts or Maymom valve for Spectra valve replacement. Made by Maymom, not by original spectra company. Maymom is not affiliated with Uzinmedicare, the trademark owner of spectra. COMPATIBLE AND INTERCHANGEABLE with Spectra pump parts. Maymom pump parts perform the same suction power as OEM parts, Spectra S2 pump parts, Spectra S1Plus accessories. MAYMOM FLANGE can work with Spectra wide-neck bottle (wide-mouth bottle), Avant bottle, and Maymom widemouth bottle. Available Flange sizes:13mm, 15mm, 17mm, 19mm, 21mm, 24mm, 25mm, 27mm, 28mm, 29mm, 30mm, 32mm. MAYMOM DUCKBILL VALVES features "easier to plug in and remove", "durable quality" and "color options" BPA/DEHP FREE. FDA compliant for food contacts. Tested by independent lab. Test report online available for reference. Products in retail pack sealed by manufacturer. No problem with dishwasher top rack, water steam cleaning, boiling water or microwave-steam bags. Contents: 2x21mm Flanges and 2 duckbills. Made by Maymom, not by original spectra company. Maymom is not affiliated with Uzinmedicare, the trademark owner of spectra.