There are three functional versions of this part:
9244a Technic Universal Joint - Old Style
This is the oldest version, used from 1972 to 1974. It is four studs long, and only known in Red.
9244 Technic Universal Joint 4L [Complete Assembly]
This is a modernized version, used from 1973 to 2009. It is four studs long and known in Light Gray and Light Bluish Gray.
61903 Technic Universal Joint 3L [Complete Assembly]
This is the modern version, introduced in 2008. It is three studs long and only known in Light Bluish Gray.
(Function Comparison Image will follow...)
Click on a colored part below to see the Sets and MOCs that use part 61903 Technic Universal Joint 3L [Complete Assembly] in that color. You can find an overview of all LEGO Colors here.
If a color is missing, it probably needs to be added to a Set Inventory.
This part has been used by MOCs in the following colors but not officially released.