This is the soft and lightweight back support that enables full range of motion while it helps improve overall posture. Made from a soft and durable four-way stretch elastic material, it fits under (or over) clothing to gently retract your shoulders into proper alignment and engage your core and lower back muscles. It has a unique figure-8 design and also has adjustable straps that help provide a custom fit. The unit is woven with copper fibers that help inhibit odor- and stain-causing bacteria, mold, and mildew. Hand wash. 85% Nylon/15% Spandex. Unisex. Sizes S/M (34"-40" chest) or L/XL (42"-48").