Available exclusively from Hammacher Schlemmer, this is the chair with a stability ball seat that strengthens the back and core, combating the detrimental effects of sitting for long hours at a desk. The curves of the latex-free seat encourage correct posture, alleviating strain and tension while toning muscles and supporting proper spinal alignment. Unlike ordinary stability balls, this innovative alternative has an adjustable padded backrest and five legs for additional reinforcement and all-day ergonomic comfort. Supports up to 176 lbs. Fits most standard desks. With five rolling, lockable caster wheels. Black. Includes manual air pump. Minor assembly.