The Spectra Duckbill Valve Set is designed to increase suction and provide better output during Breast Pumping sessions while preventing backflow contamination. Each duckbill valve is one-piece making it easier to clean and lasts longer. Spectra Duckbill Valves are made of silicone and quality tested to ensure a sturdy grip on small, medium, large, or x-large breast flanges. All Spectra Breast Pump parts that come in contact with Breast Milk are BPA/DEHP-free. Authentic Spectra Duckbill Valves are specifically designed for Spectra Breast Pump parts: establishing a proper connection to achieve best performance and quality pumping sessions. The Spectra Duckbill Valves Set comes with two white duckbill valves.