A chain breaker is a small tool used to remove links from a bicycle chain. It is typically made of metal and has a hook on one end and a pin on the other. To use a chain breaker, first, place the hook over the link you want to remove. Then, insert the pin into the hole in the link and twist the chain breaker until the link breaks.
Chain breakers are important because they allow you to easily remove and replace links from a bicycle chain. This can be necessary for a variety of reasons, such as when you need to shorten the chain or replace a damaged link. Chain breakers are also relatively inexpensive and easy to use, making them a valuable tool for any cyclist.