The endbell is the part of an electric motor where the brushes travel inward toward the armature and the commutator. Electricity is applied to this area for the motor to properly rotate. Many motors have adjustable endbells, which allow for different timing. Stock "silver can" motors usually have "closed" endbells, meaning they are not adjustable, and the brushes and springs cannot be changed. Modified motors usually have what is known as an "open" endbell, where springs and brushes are able to be changed.