S10 Drinking tube plug

This is a plug to seal off the S10 drinking tube pass through.
If you ever decide to take out the drinking tube of your S10 gas mask, for example when adding a custom speechbox grille, you need something to close the hole.

This plug creates a decent seal for me. It's not absolutely airtight, but is a good enough compromise of sealing the hole, still being removable and not falling out by itself.