Aluminum Tape (vented and non-vented) – TAPES for use with TwinWall and Multiwall Polycarbonate in Greenhouses. The Solid Non-Vented Tape is used to Cap the TOP of the Sheet so debris can not get in the flutes. The Vented Foil Tape should be applied on the bottom width edge of the polycarbonate sheets to allow condensation drainage and prevent dust and dirt to get inside the ribs. Different sizes available for panels from 4 to 45mm. Types: Vented and Non-Vented: Solid Foil Tape (Non-Vented) – Used to Cap the TOP of the Sheet so debris can not get in the flutes. Vented Foil Tape – Used on the BOTTOM of Sheet to keep debris from getting in the flutes, but allows condensation to come out. Aluminum Tapes are Made in 1″, 1.5″ and 2″ widths. 1″ wide (for 4mm-10mm sheets), 1.5″ wide (for 16mm-20mm sheets), 2″ wide (for 25mm-45mm Sheets)