Limit and snap action switches are used as part of a control system to prevent the travel of an object past a certain point to keep workers safe from malfunctioning machinery. Limit and interlock switches activate or deactivate machine power if the travel limit of an object is exceeded. Snap action switches rapidly open or close circuits. Safety interlock switches shut off power when protective doors are opened on machine tools and other pieces of equipment. Switch accessories are used to build, repair, maintain, or enhance switches.