Copied from a period shutter knob shaft that can be assembled to any suitable knob. The price includes the assembly to the knob of your choice. Order the knob/knobs separately and give your instruction in the comments section of the order form.
Length (not inc fixing stub): 2″ (51mm)
Square Section: 5/16″ (8mm)
Tapering to: 1/4″ (7mm)