The main cause of breast milk being trapped in the duckbill valve is that the air pressure inside the bottle is higher than the air pressure in the duckbill valve when there is excessive breast milk.

Please follow the steps below to prevent breast milk from being trapped in the duckbill valve:

• Ensure a tight seal between the breast and the breast pump.
• When there is a large quantity of breast milk, the excessive breast milk may become trapped in the duckbill valve. However, it will not affect the normal usage of the Breast Pump.
• Please hold the container with the flange side facing up when transferring the breast milk to prevent leakage from the tunnel.

If you have any further questions regarding the eufy Breast Pump, please don't hesitate to reach out to us for assistance.