There were three different makers of jacks! I have done some research, but never able to determine whether or not if they were used by all plants or certain ones!? Or when!? The makers were,auto specialties,universal tool and stamping, and California jack co! I know one of the designs is a solid T shape , second one was a hollow almost square, third one is either hollow or a solid Y shape!? I will see if I can find my notes! First picture is of two of the three correct bases, second is of the T style which is 34 inches tall ! Big car jacks can be used to lift the car but they don't fit in the cradle in the trunk as they are to long!