Limits air flow in one direction.Air is easily blown/sucked through one way, but not the other. This creates a one way path for air.It is not perfect - it is not fully sealed, but it increases the effort needed / slows down the air movement a lot, considering that it is a very small and simple gadget.

INSTRUCTIONS:

• Each piece has an orientation where print supports are not needed.
• The chamber must be printed in two parts and ca-glued together with the core inside, if using mdf printers or similar, but there is also a full chamber provided.
• There are two versions of the core. One is suitable for adding a custom rubber ring, if you figure out a good way to do that. The other is entirely smooth and one material, but should still work to a certain degree.

WARNING:I consider this not 100% functional, merely an experiment or test, BUT it might just be what you need.