A Universal Joint (often abbreviated as U-joint) is a mechanical device that allows for the transmission of rotary motion between two shafts that are not in a straight line. It accommodates angular misalignment, enabling the shafts to pivot and rotate at different angles while still transferring power. This is commonly used in vehicles, particularly in the drive shafts of cars and trucks. U-joints consist of a cross-shaped component with four arms, which connect to the shafts. They are essential in applications where flexibility and movement are required, such as in automobiles, industrial machinery, and aerospace systems. Proper maintenance of U-joints is crucial to ensure smooth operation and prevent wear.