Compatibilty: Perfectly fits standard 24mm breast pump shields and flanges for enhanced pumping efficiency, ensuring compatibility with brands such as Momcozy M5/M6/M9, S12 Pro, S9 Pro, V1 Pro, V2 Pro, Spectra, Medela, Elvie, and more. Note: Not compatible with 27-28mm shields. Size Options: Includes 2 pieces 19mm flange inserts for customized fit and comfort. Easy Installation: Simple to insert and remove from standard 24mm flanges, allowing quick size adjustments when needed. Safe For Baby And Mom: Made from food-grade silicone, BPA-free, easy to clean, and dishwasher safe. Includes a sponge cleaning brush. Replace breast pump flange insert every 2 months for optimal performance. Perfect Gift for New Moms: Our silicone flange inserts help mothers quickly and comfortably find the right size, ensuring a smooth pumping experience. They also enhance safety and maximize the performance of the breast pump. 4PCS Flange Insert 19mm Compatible with Momcozy M5/M6/M9/S12 Pro/S9 Pro/V1 Pro/V2 Pro, Spectra/Medela/Elvie/NCVI/TSRETE/eufy/Lansinoh/Paruu/MomMed Breast Pump 24mm Shields/Flanges