Feature: 1. Excellent Silicone: Duckbill valve and diaphragm are made of food grade silicone material, soft and skin friendly, which is safe for mothers and babies, allow you can use it at ease. 2. Wide Compatibility: Duckbill valves and silicone membrane set compatible for S18, S21, and S23 wearable breast pumps, which can provide efficient milk expression for you. 3. Regular Maintenance: Duckbill valve and silicone diaphragm set can provide optimize pump performance by replacing parts every 1‑3 months for optimal suction and comfort. 4. Easy to Cleanse: Wash duckbill valve and diaphragm with warm soapy water after each use, rinse thoroughly with hot water or steam (approx. 100°C/212°F), no dishwasher or hard brushes. 5. Enhanced Pumping: Silicone duckbill valve and diaphragm can ensure a more comfortable and effective suction by replacing parts regularly during frequent milk expression sessions. Specification: Item Type: Duckbill Valves and Silicone Membrane Material: Silicone Application: for S18, for S21, for S23. Package List: 2 x Duckbill Valve 2 x Silicone Diaphragm