Which part of an extension ladder prevents the fly section from being over-extended?

The part of an extension ladder that prevents the fly section from being over-extended is known as the stops. These are physical barriers located at the ends of the fly section that limit how far the fly section can slide out from the main section of the ladder. This safety feature is crucial as it ensures that the ladder remains stable and reduces the risk of accidents that can occur from over-extending the ladder, which may lead to structural failure or loss of balance.

The design and placement of the stops are specifically engineered to maintain the proper function and safety standard of the ladder while in use. This feature protects both the user and the equipment by ensuring that all parts operate within safe limits.