Attributes . B580 Executive Web Chair1 x Back1 x Seat1 x Left Arm1 x Right Arm1 x Mechanism1 x Gas Lift1 x Base5 x Casters1 x Knob8 x (M6 x 30mm) Arm Screw4 x (M8 x 22mm) Mechanism Screw4 x (M8 x 30mm) Back Bar Screw . Names