A ratchet, also known as a ratchet wrench or socket wrench, is a hand tool used for tightening or loosening fasteners. It is designed with a ratcheting mechanism that allows for continuous rotation in one direction while preventing backward movement. Ratchets are commonly used in automotive repair, construction, and other applications that involve fastening or unfastening bolts, nuts, and screws. Here are some common types of ratchet: