Functions: The belt is stretchable with a rubber band, convenient to adjust. Portable design, USB charging, convenient for use and carrying. It can be used at home and in travel. Made of quality material, safe and durable for use. Conform to ergonomic design, and fit well with body parts. Features: Infrared LED light goes deep into joints and soft tissue, effective physiotherapy. Suitable for soothing muscle and relieving shoulder pain, make you relax. Help to promote blood circulation, a good assistant tool for the treatment of arthritis. Product Details: Color: Black Led number: 105pcs Wavelength: 660nm/850nm Input Voltage: 5V Notice: Indoor use only: Light is not waterproof, and can not use in water or wet places.