UNIVERSAL JOINT U004
A unit used to connect two rotating parts that are misaligned. Obviously not of much use in the centrifugal pump business where alignment is critical to successful mechanical seal operation.
If you would like to see a universal joint, look at the piece of hardware that is connecting the drive shaft of your automobile to the transmission
Universal joints allow freedom of movement in just about any direction.
It might also be important to note that a universal joint has to be misaligned to receive proper lubrication.