This is a seat cushion called "Magu Mat Premium Advance" sold by "PROIDEA." It was developed based on the shape of a riding saddle ("kura"), and is designed to support the pelvis and maintain good posture simply by sitting on it. Main Features: Posture Support Like a horse saddle, it wraps around the buttocks from front, back, left, and right, reducing the burden on the lower back and back. Multi-Layer Structure The Advance model, for example, uses a 4-layer cushion structure including special gel, providing both softness and stable sitting comfort. Uses It can be used as a floor seat, or placed on a chair as a cushion.