The A400 Compression Half Tight is not a thermal tight. Instead, its 76% nylon microfiber/24% spandex makeup has just the right amount of stretch for perfectly controlled compression. Its 400 Fit uses 400 key fitting points designed with measurements from hundreds of athletes. The design uniquely wraps and supports your key muscle groups for less movement, vibration and soreness after exercise. Memory MX Panels use a high-stretch elastomeric yarn with the ability to retain their shape, despite high levels of stress. Permanent antimicrobial treatment in the fabric discourages bacteria and odor-causing substances normally associated with Lycra wear. Imported.