With 4 LED flashing lights * 3M reflective technology; Invisible electronic switch control - 3 status of LED lights(steady, flashing and off ) * Included a CR2032 battery * Max. bound diameter: 6.3 inches, Min. bound diameter: 2.4 inches. Dimensions (L*W) 14.7 x 1.1 inches * Package included: 5 velcro bands