Puncture proof ergonomic chair. Contoured seat and back provide comfortable support. Puncture and tear resistant black polyurethane foam with tough outer self-skin performs maintenance free in tough environments. Independent seat and back tilt angle adjustment allow personalized positioning. Backrest features 35″ to 42″H and 2″D adjustments. 16″ to 21″ pneumatic seat height adjust. Seat: 18-1/2″W x 17″D x 2″ Back: 16-1/2″W x 12″H. Strong 5 blade base includes both casters for mobile use and glides for stationary use. Available with or without arms. Easy assembly.