Ergonomic pelvic posture correction slim cushion. - Material: Synthetic leather - Uses: Posture correction, dieting - Features: Ergonomic design Thank you for viewing. By simply sitting on this cushion for about 15 minutes a day, the angle and your own weight will tighten the skeletal structure around your waist, naturally tightening the opened pelvis. The firm foam provides moderate elasticity, firmly supporting the ischial bones, which are the lowest bones when you sit. The curve on the bottom receives your weight and sinks in, correcting it inward. I previously purchased it for around 10,000 yen. There are some areas that have discolored due to aging (please check the photos), but there are no functional problems at all. Perfect for postpartum recovery, dieting, and posture correction.