From Tyvek
Roofing: Pitched RoofThis multi-purpose self-adhesive FlexWrap tape is quick and easy to use and can get the job done 50% faster than standard tapes and seals on the market, and require no additional fixings. Compatible with a huge choice of building materials and will adapt to common and uncommon shapes from windows to chimney breasts, creating a water-tight and air-tight seal that will withstand the elements. It does not allow gaps and leaks to occur, ensuring airtight and watertight protection. It has a durable top sheet, a butyl adhesive layer, and a split release liner. Packaged in ready to use seals - no additional fixings are required Superior durability Air and watertight seals Superior protection Excellent adhesion performance