These plugs come standard with all of our formicaria, made by combining vinyl tubing and a plastic piece on one end. The vinyl stays flexible, and the hard part grows the vinyl diameter slightly, creating a perfect seal against the opening.
 
Best of all, they are reusable; if the vinyl tube wears off, you can cut a new piece and re-use the hard plug portion. 
 
The plugs are available in both of our standard sizes 9.5 mm (3/8") and 12.7 mm (1/2"). It's always a good idea to get a few extra in case a plug suddenly goes missing.
 
The plastic piece is made with PLA Pro plastic.