Esd chair ergonomically designed production chairs 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 17-1/2 to 22-1/2″ for chairs. This esd model is static-dissipative with a resistance of less than 106 ohms, and has a drag chain for proper grounding. Easy assembly.