Metl-Span’s BW Universal System and BW Stretch System are backup wall systems, providing air, water, thermal and vapor protection in an all-in-one barrier component. The BW Universal System can be horizontally installed with nearly any type of exterior rainscreen system and can span up to 24 inches on center. The BW Stretch System can be vertically installed with multiple types of exterior rainscreen systems and can span up to 6 feet on center. Both new systems are installed in a single step, eliminating the need for multiple work crews, expediting close-in/dry-in building times, and reducing the likelihood of improper installation.