Master Massage engineers designed this stool for better comfort and designits saddle nature eases painful pressure on the back. The 2.5" exclusive Molded foam is specially molded around the seat base, rather than simply glued on. The Master Ergonomic Adjustable Saddle Stool boasts a large, comfortable 360 swivel seat, soft Rollerblade-like Polyurethane wheels (safe for hardwood floors and carpet), and hypoallergenic durable upholstery. The seat's PU upholstery is hypoallergenic, CFC-free and oil and waterproof, making it perfect for dozens of workplaces and professions. Each element of the stool has been engineered for comfort, stability and longevity. PERFECT for professionals and for at home use.