CONTENTS: 2 Shields (12 mm), 2 Wide-mouth Connectors. 12 mm shield is suitable for mothers with nipple diameter 10-11 mm AFTER pumping. The shield and connector constitute a breast pump flange. This set works for double pumping. | FEATURES: Separable TWO-PIECE flange for Spectra pump, NOT like one-piece Spectra flange. Made by Maymom. Two-piece construction is preferable for easy assembly, disassembly and cleaning. It also fits most hands-free pumping bra on the market and home-made bra. Available shield sizes: 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 27mm, 28mm, 30mm, 32mm, 34mm, and 36 mm. | COMPATIBILITY: This set is compatible with Spectra Pump S1, Spectra S2, Spectra 9 Plus. Compatible ONLY with widemouth (wide-neck) bottle, like Spectra wide-neck bottle, Avent bottle, Maymom widemouth bottle. They are NOT compatible with OTHER widemouth bottles. To make it compatible with Medela bottles, try Maymom 3rd Gen Bottle Converter (Amazon ASIN: B07MGSNJYJ). | REGULATIONS: All parts that come in contact with breast milk are BPA/DEHP free. Made by a US FDA inspected company, Maymom. Refer to her online access for test reports. Dishwasher top rack safe; steam safe sterilization. | RETAIL POLY-BAG PACKED; sealed by the manufacturer, Maymom. NOT original Spectra flange, NOT original Spectra pump parts. NOT original Spectra S2 Accessories. NOT original Spectra S1 accessories.