Self-adhesive cotton covers for monotub holes. Tooled to a drawing at 65 mm (about 2.5") outside diameter with a 50 mm (just under 2") open window, so a standard 2" hole stays almost entirely open. Six per sheet, which covers one tub on our monotub build.

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

• 65 mm OD, 50 mm open window. On a 2" (50.8 mm) hole, the adhesive overlaps the edge by less than half a millimeter per side, so about 97% of the hole stays open.

• Gas exchange with slower moisture loss. Tight-weave cotton passes air freely while slowing evaporation, so your RH stays where you set it.

• Annular adhesive, not full-face. The adhesive sits on a 7.5 mm (0.3") ring around the perimeter, so the cotton over the hole stays fully open.

• 3M 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. The adhesive sits on a narrow outer ring, so the whole window over the hole is open for exchange. 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.