VYCOR® Butyl, formally VYCOR®PRO, features the same proven flashing technology and installation practices professionals have trusted for years. VYCOR® Butyl flashing tape helps protect vulnerable wall openings by creating a durable barrier against water and air infiltration around windows, doors, and other critical transitions. Its non-asphaltic, butyl-modified adhesive delivers strong adhesion, seals around fasteners, and conforms to a variety of building materials for reliable, long-term protection. Available in 4”, 6", 9" and 12" " widths, VYCOR® Butyl offers installation flexibility to accommodate a variety of flashing and detailing requirements. Unlike many traditional non-butyl or asphalt-based flashing products, VYCOR® Butyl offers superior material compatibility, including use with rigid and flexible PVC window flanges and modern sealant technologies. The highly conformable membrane seals around fasteners, forms watertight laps, and adheres reliably to irregular surfaces...See More for enhanced protection in demanding applications As part of a complete CertainTeed weatherproofing system, VYCOR® Butyl works with weather-resistive barriers and siding products to help manage moisture, improve energy efficiency, and create a more resilient building envelope. Together, these components help protect against water damage, mold, rot, and air leakage while supporting the long-term performance of the exterior wall assembly. Available Sizes 4 in. x 75 ft. 6 in. x 75 ft. 9 in. x 75 ft. 12 in. x 75 ft. See Less