3M Outdoor Insulator Film Mounting Tape, .5-Inch by 13.8-Yard Window Mounting Tape For Window Insulating Kits Use With 3M Outdoor Window Kits The half-inch in tape width makes it easy to apply around window frames and casings The tape is easy to apply and has a ready-to-peel liner Creates a strong bond between the surface, tape and film, securing an air tight seal Shrinks tight for wrinkle-free, clear-as-glass results Increases R-value by 90% over an average single pane window.