A. The breast pump flange inserts are made of silicone material, which are sturdy and useful. They can be used for electric breast pumps and wearable breast pumps. They are simple and easy to replace, and convenient to use. They are considered safe and good, simple and convenient, as well as sturdy and practical. B. Features - Color: As Shown - Material: Silicone - Size: 4.60X4.60X3.40cm/1.81X1.81X1.34in - Note: Available in sizes 13mm, 15mm, 17mm, 18mm, 19mm, 20mm, 21mm, 24mm. - Made of silicone material, the flange inserts are thought to be safe and practical, sturdy and useful, and can serve for a relatively long period. - With a smooth surface and no rough burrs, the breast pump flange inserts are regarded as good and sturdy, not likely to hurt your skin, and comfortable to use. - They have a fine texture, are simple to replace, and are considered safe and useful. The wearable breast pump flange inserts are practical and good. - They have good performance, a simple design, and a reasonable design. You can use the breast pump flange inserts with a certain degree of confidence. - They are suitable for wearable breast pumps and electric breast pumps, are simple to use, and bring a certain amount of convenience to you. C. Packing list: - 1 x breast pump flange insert 24mm - 1 x breast pump flange insert 21mm - 1 x breast pump flange insert 20mm - 1 x breast pump flange insert 19mm - 1 x breast pump flange insert 18mm - 1 x breast pump flange insert 17mm - 1 x breast pump flange insert 15mm - 1 x breast pump flange insert 13mm