Why Material Selection Matters When Developing Silicone Valve Seal
https://siliconesealstudio.wpsuo.com/nbr-valves-for-one-way-flow-control-in-practical-product-designs
A reliable product depends on parts that do their job every time. A silicone valve seal can support clean use when its shape and material match the task. It is not enough to choose a part by name only