The UV meter wristband/bracelet is a very good marketing premium. You can use it to check solar UV radiation index levels: UV Index 1 (low), SPF & lt 5, UV Index 3-5 (mod), SPF & lt 10, UV Index 6-7 (high), SPF & lt 30, UV Index 8-10/11+ (extreme), SPF & lt 50+. The higher the solar UV radiation, the darker the color change. Enjoy the sun and avoid sunburn with Ever King's Solar UV bracelet now. 9" L x 1 1/2" W