When using a kiln sitter, you need to determine which pyrometric item you will use. To begin, we can narrow the field down somewhat by eliminating large pyrometric cones, including those that are self-supporting. Small cones (sometimes referred to as junior cones) were developed for use in electric kiln sitters. Later, pyrometric rods were also developed.
The difference between the small cones and the rods is that the rods do not taper. Thus, rods consistently bend enough to shut off the kiln at the cone they are rated for. This is not the case for small cones.
If the small cone is placed to one side or another, the experienced potter can adjust the kiln's ending temperature by a noticeable amount. Centered on the prongs, the small cone will bend (shutting down the kiln) at the proscribed cone rating. If the lever bar is resting on a thicker portion, it will be a hard firing. If the lever bar is resting on the thinner portion, it is the equivalent of a tipped firing.