1. Material: ABS + PVC 2. Dimensions: inner diameter 25 cm, outer diameter 37 cm 3. Use crowd: for all ages 4. Function: waist exercise, relieve fatigue, strengthen body, reduce fat and shape 5. Small size, easy to carry, built-in steel ball pure physical vibration, site restrictions 6. The multi-function display screen records the number of revolutions, time and calories in real time 7. Hold the fitness ring with both hands, open the buckle of the fitness ring, and pull out the telescopic tube to adjust the size