The MKM Shoulder Tool is excellent for adjusting the angle and break of the shoulder of a pot. On a narrow mouthed bottle or jar form where it is no longer possible to insert your hand or finger, you can use the shoulder tool to form and support the shoulder. It will fit through a very narrow opening. If the shoulder begins to collapse, use a hair dryer or heat gun to dry out the clay in the shoulder area, and then use the MKM Shoulder Tool to reshape the shoulder, and to lift the break between the shoulder and the main wall of the form.
Although this is a relatively small tool, it is amazing how useful it can be on large forms as well. The tool extends out 7 inches (17.5 cm), and it is a rare pot that has a shoulder wider than 14 inches in diamter.