This belt utilizes four key elements: tourmaline, far-infrared rays, 20 magnets, and self-heating through body temperature, to help reduce stress on the lower back. You should feel the area around the belt warming up. It's also effective for women's issues like menstruation and for relieving coldness in the abdomen. It's recommended to wear it over an undershirt or with a towel in between. The belt is made of highly elastic mesh for breathability, reducing stuffiness in the summer heat. When washing, gently rinse with water and let it dry. It can be used repeatedly. 【Product Specifications】 L Size: Approximately 81cm-110cm