Made of high quality OK cloth + tourmaline + self-heating strap, is lightweight, soft, skin-friendly, breathable, comfortable, warm and durable, very easy to wear. Black Size: 45*9.5 cm/17.5*3.7inch, one size fits for most of men and women. Grey and red size: 43*10cm/16.8*3.9inch, fits for most of womens This will help a lot the self heating magnets do work and produce sufficient heat to the neck. It's great for helping to relieve the tension and pain in neck caused by an on-going medical problem. Which can reduce the amount of analgesics you take Tourmaline magnetic neck brace can improve partial and whole body's blood circulation, promote fracture healing and improve neck strength,reduce back, shoulder and neck pains, accelerate soft tissue healing, improve the joint flexibility and increase extensibility of collagen tissues Suitable for minor injuries, sprains, twists caused by sports or arthritis. Fits great and very comfortable to wear for acute pain, muscle spasms, chronic stiffness and tension in the head area Small enough to keep in your handbag wherever you go, it's always within easy reach when you need it. Recommends 20 minutes for safety trial, better time is 45-60 minutes per day