Usage guidance:● From stretching exercises, you can exercise such as tightening your back muscles and arms, and strengthening your abdominal muscles.● Please use with your own load by adjusting the air pressure.● From simple balance exercise to high-speed posture● By sitting on a donut ball, the pelvis is pinched on the inner side of the central hole, tightening the pelvis from the left and right with your own weight, which is effective for opening pelvis correction.* This product is for general household use. Do not use it in training facilities used by an unspecified number of people.* Be sure to keep the load capacity.* The maximum size may not be reached with a single inflator.* By putting it in several times, the rubber will become familiar and it will be easier for air to enter.* Be sure to lay a mat etc. before use.Precautions for useThe diameter listed on the product page is the maximum diameter. Due to the characteristics of the load-bearing material, the ball is hard at the beginning of use and may not expand to the maximum diameter at one time. If you want to get closer to the maximum diameter, slowly inflate it (about 5 times an hour).