A swivel joint is a mechanical device that allows two connected parts to rotate relative to each other while maintaining a fluid or gas connection. Commonly used in various industries, swivel joints are essential in applications like hydraulic systems, where they enable movement without compromising the integrity of the connection. These joints are designed to handle high pressure and can be found in equipment such as cranes, excavators, and oil rigs. By facilitating smooth rotation, swivel joints help improve the efficiency and functionality of machinery, making them vital components in many engineering applications.