Features: Ensure a comfortable and efficient pumping experience with our 24mm/27mm flange size, specifically designed to be compatible for S18 S21 wearable breast pumps. Our replacement pump part set features a duck mouth valves and silicone diaphragm, ensuring safety and durability for mother during their breastfeeding journey. Tailored for nursing mother in need of convenient lactation support, these accessories are suitable for S18 S21 breast pumps users seeking reliable replacements. Whether at home, in the hospital, or while traveling, our milk collector cup and pump accessories offer ease and efficiency for breastfeeding moms travel. The easy to clean designing and simple assembly of our wearable breast pump accessories make them a easy solution for maintaining your pump's performances. Specifications: Component: PP+Silicone Type: 24mm, 27mm(optional) Valves: 20x25mm/0.8x1inch Dustproof cover: 115x125mm/4.5x4.9inch Diaphragm: 55x40mm/2.2x1.6inch Applicable Model: for S18/S21 Wearable Breast Pumps Quantity: 5pcs/set Package Includes: 1 Set Breast Pump Accessories note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.