Safco Products 3391BL Alday 24/7 Task Chair (Optional arms sold separately), Black Alday 24/7 big and tall office chair with weight capacity up to 500 lbs. Fabric upholstered seat and back with supportive ergonomic cushioning Features pneumatic seat height adjustment 17 1/2" to 20", 360 degree swivel, tilt adjust with tilt tension and tilt lock, back height adjustment Heavy duty five star steel base with 2 1/2" dual wheel carpet casters Safco Products optional Adjustable T-Pad arms Model 3399BL available, sold separately