Self-adhesive cotton covers for monotub holes. Tooled to spec at 2.5" (65mm) outside diameter with a 2" (50mm) open window, so a standard 2" hole gets full coverage with no dead zone under the adhesive. Six per sheet, which is exactly one standard monotub.

Perfect For

• Standard monotub builds with 2" holes

• Smaller hole diameters down to 1"

• Anyone following the Myco Powered monotub build

Why Growers Choose These

• 2.5" (65mm) OD, 2" (50mm) open window. Sized so the breathable area matches the hole. You lose nothing to the adhesive ring.

• Gas exchange without losing humidity. Tight-weave cotton passes air freely while slowing moisture loss, so your RH stays where you set it.

• Annular adhesive, not full-face. The adhesive sits in a 0.3" (7.5mm) ring around the perimeter. The entire cotton surface stays open, unlike discs with adhesive across the back that glue part of the material shut.

• 3M high-temp adhesive. Mounts to the dry exterior of the tub, so the bond never sees standing water or condensation.

• Six per sheet, one sheet per tub. No counting, no leftovers, no partial coverage.

• Fits 2" holes and smaller. Run smaller and still get full adhesive contact.

• Set and forget. No layering, no adjusting, no re-taping between grows. The exchange rate is fixed by the weave and the window size, so a tub built with these behaves the same way every run.

The Myco Powered Difference

These were tooled to a drawing, not pulled from a catalog. Most covers on the market use adhesive across the entire back, which glues a portion of the material shut and cuts your exchange. These don't. Six per sheet matches the hole count on the monotub build we recommend, so a sheet is a tub.

One sheet, one tub. Order by the number of tubs you're running.