The Ameda HygieniKit Breast Pump Parts include silicone replacement valves that are BPA and DEHP free, ensuring a safe pumping experience for mothers. These valves are designed to preserve pump suction while allowing milk to flow into a milk storage container. Made with flexible silicone material, they aid in the process of expressing breast milk during a pumping session. Compatible with several of Ameda's hospital-strength personal pumps and multi-user breast pumps, these valves should be replaced every 8-12 weeks for optimal performance.