Vapor Permeable Butyl Tape is made of flexible, waterproof, moisture-permeable multi-layer composite substrate, used for sealing the joints between window and door frames and wall and fixed steel parts on the outdoor side of passive doors and windows, waterproof, preventing condensation and mold, and strong anti-aging. As a kind of self-adhesive waterproof vapor permeable membrane, it is mainly used in the maintenance structure of ultra-low energy buildings and on the outside of windows and doors as an airtight vapor permeable material.