1. Material: ABS 2. 360 degree omnidirectional surround massage without turning back pain 3. The gravity hammer is safe and non-slip to prevent falling 4. The 0.4kg weight ball slides by inertia and will not turn for a long time 5. It is suitable for postpartum mothers, office workers, and students to strengthen their bodies and exercise abdominal muscles 6. Simple disassembly and assembly, easy to carry