Keeps people active when they are sitting, while strengthening the body’s core and legs and improving posture. Upholstered in durable black leather-like material for easy maintenance and cleaning, or in fabric for a softer touch. Counter-balanced, stable base safely moves with you, and rests naturally upright so you can sit normally without rocking or balancing. Rubberized coating is non-skid, non-scratch and grips most surfaces. 360 actuator ring to raise and lower the seat. Adjustable seat height is 18.5-26.75"H, Diameter: Seat 14"W, Base 15". Manufacturer Lifetime Warranty. Sold as each.