Size: 75cm diameter, generally recommended for people taller than 1.73m (5'8") for proper sitting posture where hips are level with knees. Material: Made from durable, often latex-free, burst-resistant rubber or PVC. Versatility: Used for Pilates, yoga, general fitness, strengthening core muscles (abs, back, pelvic floor), improving balance, coordination, and flexibility, and even as an ergonomic office chair to relieve back pain. Accessories: Usually includes a hand or foot pump for easy inflat