On the bark portion, the reed maker binds on one, two, or three coils or loops of brass wire to aid in the final forming process. The exact placement of these loops can vary somewhat depending on the reed maker. The bound reed blank is then wrapped with thick cotton or linen thread to protect it, and a conical steel mandrel (which sometimes has been heated in a flame) is quickly inserted in between the blades. Using a special pair of pliers, the reed maker presses down the cane, making it conform to the shape of the mandrel. (The steam generated by the heated mandrel causes the cane to permanently assume the shape of the mandrel.) The upper portion of the cavity thus created is called the "throat", and its shape has an influence on the final playing characteristics of the reed. The lower, mostly cylindrical portion will be reamed out with a special tool called a reamer, allowing the reed to fit on the bocal.