These clean room chairs have been tested to Fed Std.209E and ISO 14644-1 requirements (Class10 or ISO Class 4). Optional 6 way adjustable arm rests support a variety of arm placements for proper ergonomics (Note: Adding arms changes the classification to Class 100 or ISO Class 5). The polyurethane chairs are fully washable, making them ideal for almost any environment. Choose from chrome hooded rolling, non-marring castersnon-marring bell glides on a polished cast aluminum base. Optional seat tilt provides 8 forward and 3 backward locking tilt for ergonomic posture support.