What is a breast pump flange?The flange is the part that comes into contact with your breast forming a vacuum seal which helps create the necessary suction to extract milk. These flanges are uniquely designed to fit with the Fraupow pump and ensure effective suction and ultimate comfort. Size does matter when it comes to the flange, see our size chart (scroll through the images above) to ensure you order the correct fit for you. What is the difference between an Insert and a Flange?The Flange, also called a Shield is the funnel shaped silicone part of your breast pump that fits on your breast. The hole/tunnel draws your nipple in to extract milk. The size of your flange indicates the diameter of the tunnel. An Insert is a smaller plastic part that is inserted into your flange to narrow the tunnel if needed. Features: Super soft and comfortable on the breast Made with food grade silicone & BPA free For use with the Fraupow wearable pump only. Please note, the pump comes with a 24mm flan