Razertip heavy-duty #7 cord. A 12" version of the #1 cord is available for use as a patch cord on Colwood burners.
Standard "FL" cords (black plugs) use an 18-gauge cord for maximum flexibility. Heavy-Duty cords (red plugs) use a 16-gauge cord for maximum current flow, but it is not quite as flexible. For fastest tip heat recovery the heavy duty cord is recommended. Any of our pens work on either cord, but heavy duty and Feather Former pens/tips work best with heavy duty cords.