Kit Contents: The incl. 14mm flanges are not suitable for all mothers. Please refer to the size guidance in the product listing before purchase. Kit Contents: 2 Flanges (14mm), 2 Duckbill Valves, 2 Backflow Protectors, 2 Tubes, and 2 Bottles with One-Piece Travel Caps. Compatible with Spectra S2, Spectra S1, and Spectra 9 Plus breast pumps. All pump parts made by Maymom. Not Original Spectra S2 Accessories. Not Original Spectra S1 Accessories. Not Original Spectra Pump Parts. Compatible and interchangeable with Spectra pump parts. Same suction power as OEM parts. Replace Spectra Flanges, Spectra Duckbill Valves, Spectra Backflow Protectors, Spectra Tubings, Spectra Bottles (Wide Mouth). Multiple flange sizes available: 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 27mm, 28mm, 30mm, 32mm. The One-piece cap of Maymom bottle includes sealing ring for secure seal. NO waste of milkdrop. Designed for travel and storage of formula or breast milk. It's also perfect to convert baby feeding bottle to snack container or tumbler for mommy. US FDA registered medical device (No. D192499), Health Canada License (No.26003), Australian Health and Aged Care (ID 463470). Inspected by US FDA. Comply with FDA/EU regulations for plastic materials that contact food. Test reports are conducted by independent lab and available online for reference. Material does NOT contain any BPA. Can be cleaned with water steam, boiling water or microwave-steam bags. Retail packed, sealed by the manufacturer - Maymom, not original Spectra parts. Maymom Pump Parts Compatible with Spectra S2 S1, 14mm Flange Valve Tube Bottle Backflow Protector, Not Original Spectra S2 Replacement Pump Parts Duckbill Valve Bottle