Features: Prevent breastfeeding milk backflow with this efficient duckbill valves or membrane for electric breast pump. Easy to install and clean, suitable for breast pump model. Designed for breastfeeding moms, a must have for those using breast pumps. Whether at home or work, the membrane is essential accessories for easy pumping, enjoy uninterrupted milk expression. Enhances your breastfeeding journey with this essential pumping part that ensures smooth and continuous session. Specifications: Component: Silicone Type: 6pcs duckbill valves & 4pcs diaphragm set, 6pcs diaphragms, 4pcs diaphragms, 8pcs duckbill valves, 4pcs duckbill valves, 1pc diaphragm, 1pc duckbill valves(optional) Valves: about 23x12mm/0.9x0.47" Diaphragm: about 43mm/1.69inch Package Includes: 1pc or 1 Set Breast Pump Diaphragm or Duckbill Valves(optional) note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.