Drive shaft question

I never understood what was meant by a *7260" or a "1350" or a 7290 or whatever other number is assigned to a yoke/ u joint
it's the size of the joint.
7260/7290 are the "dodge" numbers vs 13 series for basically everybody else.

naturally there's a little more to it-- type of bearings, locking mechanisms and location, etx.

yokes come in different ratings and thus sizes so naturally the joints would as well.