What are end stop screws?

End stop screws: These allow you to adjust the end point of the movement on the front and rear derailleurs. This should also be adjusted meticulously, otherwise your chain could fall off the pinion or chainring, which can be very annoying.

End stop screws:
 This allows you to adjust the end point of the movement on the front and rear derailleurs. This should also be adjusted meticulously, otherwise your chain could fall off the pinion or chainring, which can be very annoying.

Relevant articles:
Adjusting the front derailleur , adjusting the rear derailleur