1. Ergonomically designed joint track, long-term rotation without hurting the waist 2. 72 groups of wave massage bumps, no sticking or pinching, 360-degree surround massage 3. 5cm small rail design, free combination and flexible splicing, fit waistline 4. 1.5 lb gravity pellets, continuous fat consumption 5. Upgraded 4-wheel metal axle, with 28 balls built into the bearing, the speed is smoother and easier to rotate without jamming 6. Smooth and burr-free, close to the skin, comfortable and durable 7. Suitable waistline can grow with the number of sections: -12 Sections Suitable for Waist: 50-75cm -18 sections suitable for waist circumference: 50-103cm -21 sections suitable for waist circumference: 50-115cm -24 knots Suitable for waist circumference: 50-127cm - Up to 36 knots can be assembled, suitable for a waist circumference of 160cm