This is the knob for the Universal Plus mixer. It does not include the electric switch inside.
To remove your old knob, pull it straight out from the face of the mixer. Pliers can be used, but don't try to get behind the knob, as this could scratch your mixer; rather, just grasp the part of the old knob that you'd normally grasp with your fingers, and pull straight outward. The new knob installs by simply pushing it straight inward. Instructions are included with the knob for ensuring that the inner switch is oriented correctly before pushing the new knob into place.