Zinc Expansion Joint #40 is a two-piece, slip joint that finishes butt ends of adjacent panels in wide or tall walls and ceilings to allow for multi-directional movement. Panels are attached to parallel studs through the expansion joint flanges, enabling the finished surface to expand or contract naturally without cracking. #40 is ideal for joining dissimilar wall types such as wood framing to CMU and at construction joints. Adjustable expansion opening or reveal is 1/4" to 5/8". Additional weather shields should be installed behind the joint to enhance the weather resistance of this system.