Sill pans, arched windows and other curved penetrations complicate installs. FortiFlex® Butyl is a flexible, self-adhering waterproof flashing that is highly conformable, making it ideal for use in these applications. FortiFlex Butyl is constructed from a technically advanced hybrid butyl compound and a high-performance creped film that features exceptional stretch and durability. Features Exceptional flexibility Installs at low temps 12 month UV resistance Seals around fasteners Aggressive, high tack adhesion Meets AAMA 711-Level 3 Part of a complete Moisture Control System