Universal joints transmit torque and rotational motion from one drive shaft to another while allowing full free movement of the joint. These couplings, also known as Cardan or Hooke's joints, consist of two hubs that are connected to a center block with pins, forming a joint. The hubs move independently at an angle to the center block to accommodate misalignment between the shafts. Universal joint boots cover universal joints to retain lubricants and protect against contaminants such as dirt or moisture, which helps extend the life of the joint. Universal joints and boots are used in a wide variety of applications, including automotive drive shafts, centrifugal fans and blowers, medical equipment, and electronic devices.