Ergonomically designed production stools provide hours of comfortable seating. Standard on all seating: 18″ sq. seat, 16″W x 13″H back with 2-1/2″ thick foam padding, adjustable seat depth and reinforced black nylon bases with dual-wheel casters. Pneumatic height adjustment from 19 to 27″ for stools. Stool has adjustable chrome plated foot ring. ESD models are static-dissipative with a resistance of less than 106 ohms, and have a drag chain for proper grounding. Only the non-ESD fabric chairs are Scotchgard treated. Easy assembly.