This product relies on the principle of arc stretching, can help you solve the waist pain, fatigue, waist weakness, waist stiffness, lumbar discomfort'problems, extend your waist muscle lines. Features: The 3 gear can be adjusted, and the back bow angle can be adjusted according to needs, so as to suit waist exercise needs. Simulation finger massage, acupuncture touch, advanced PP material, durable, there are 150 massage contacts. Arc stretching, for laying and sitting. Specifications: Material:PP Product color: random color Product design: W1 acupuncture colorful style, W2 black yoga belt style. Product size: 40*27*3 Product function: correcting spine, improving hunchback / waist acid Instructions: 1. Put the spinal correction plate on the bed or stall, adjust the appropriate tensile strength. 2. Place the spinal correction plate behind the buttocks, and the rear part of the product faces the buttocks. 3. Lie down slowly. 4. Correct posture: sideways and arm support. Notes: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! 2. Please allow slight measuring deviation due to manual measurement.