This is a special order item. Est. arrival at B&H is 2-4 weeks (subject to availability). Your order will be charged at the time of shipment.
The Arca-Swiss Friction Knob for Monoball Z Series is a replacement knob for the Arca-Swiss Z series monoballs--Z1, Z2, and Z1g--which controls the rate of movement when moving the camera on the mount.