Only tried on once. Gray L size (waist 70-85cm, length 30cm) *Unisex belly band Material: 58% Polyester, 38% Cotton, 4% Polyurethane "BS Fine," a new fiber developed by Kamo Fiber in Tsuyama City, Okayama Prefecture, incorporates black silica, and is said to be like "wearing a rock bath," providing a comfortable warmth through far-infrared rays. Unlike conventional belly bands, the BS Fine Waist Warmer has excellent fabric elasticity and fits the body gently without feeling restrictive. Simply wearing it around your abdomen warms your body from the inside. It's thin, so it doesn't show under your outerwear. The "single-bag border fabric" used is a belly band-exclusive fabric with a two-layer structure of BS Fine, cotton, and polyurethane. The inclusion of polyurethane enhances elasticity, reducing tightness and making it comfortable to wear at night. 【BS Fine】is a new fiber that incorporates natural mineral black silica (Shinten Stone) into polyester using cutting-edge technology. Because 0.3-micron natural mineral is enclosed in the center (core-sheath structure) of 3-micron polyester fibers, the effect does not change at all even after washing. Furthermore, by making it finer, the surface area of black silica increases, and its power is successfully drawn out efficiently. The "wearing a rock bath" BSFINE series warms the body to the core with far-infrared rays from black silica, without causing sweatiness, and provides a comfortable warmth.