These cleanroom chairs have been tested to Fed Std.209E and ISO 14644-1 requirement (Class 100 or ISO Class 5). Optional 6-way adjustable armrests support a variety of arm placements for proper ergonomics. Additional ergonomic benefits include a contoured waterfall seat cushion and an adjustable backrest with lumbar support for increased comfort during extended sitting durations. Class 100 Clean Room chairs are constructed of highly durable molded polyurethane foam cushioning covered with easily cleaned antibacterial or antimicrobial vinyl in over 65 standard and custom colors. Optional seat tilt provides 8 forward and 3 backward locking tilts for ergonomic posture support. These bench height chairs feature your choice of chrome-hooded casters or glide on a polished cast aluminum base.