Work chairs shall be steady, allow the user freedom of movement and enable a stable, comfortable position. If necessary, the chair shall prevent the transmission of vibrations.If there is a risk of unfortunate muscular strain, for example in connection with work at a computer screen, it must be possible to adjust the height of the seat and the height and tilt of the backrest. If necessary, it must also be possible to regulate the depth of the seat.A footrest shall be made available on request.It must be possible to install arm rests as required.