1. The breast pump flange inserts are made of silicone material, which is 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 safe and of good quality, simple and convenient, sturdy and practical. 2. Features - Color: As Shown - Material: Silicone - Size: 4.60X4.60X3.40cm/1.81X1.81X1.34in - Note: 13mm, 15mm, 17mm, 18mm, 19mm, 20mm, 21mm, 24mm. 3. Made of silicone material, the flange inserts are safe and practical, sturdy and useful, and can serve for a relatively long period. 4. With a smooth surface and no rough burrs, the breast pump flange inserts are good and sturdy, not hurting your skin and comfortable to use. 5. They have a fine texture, are simple to replace, safe and useful. The wearable breast pump flange inserts are practical. 6. They perform well, have a simple and reasonable design. You can use the breast pump flange inserts with confidence. 7. They are suitable for wearable breast pumps and electric breast pumps, are simple to use, and bring much convenience to you. 8. 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