Essential for New Moms: Nursi Luna Flange Sizing Kit 3 in 1, developed by an IBCLC (International Board Certified Lactation Consultant), enhances comfort and pumping efficiency for new moms, addressing common confusion and discomfort during breastfeeding. Highly Compatible: 10Pcs Flange sizing kit come in a variety of sizes to choose from 13/15/17/19/21mm (2 flange inserts of each size) Fits most pumps with 24mm flanges/shields. Note: Not compatible with 27-28mm shields Getting The Right Flange Size: Nipple size can change during different breastfeeding stages, requiring adjustments for optimal comfort. Our nipple ruler based on IBCLC recommendations, provides precise sizing to ensure a perfect fit and efficient pumping 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