The “tractor side” terminal of the agricultural cardans is coupled to the power take-off (PTO) of the tractors which, following international standards (DIN 9611), can be of 4 different sizes, as shown in Table 1:

A	Z6 tip 1 3/8"				Z20 1 3/4"
B	Z6 tip 1 3/8"				Z6 1 3/4"
C	Z6 tip 1 3/8"				1 1/4" hex
D	Z6 tip 1 3/8"				1 1/8" hex
E	Z6 tip 1 3/8"				Z21 1 3/8"

Aemco adapters consist of a hub and tip. They allow the use of the standard cardan shaft for Power Take-off (PTO) shafts of type A above (6 splines and Ø 1 ⅜”) in other tractors that have PTO with measurements of types B, C, and D. This way, you don't need to have 1 cardan for each PTO measure. Therefore, adapters are standard with 6 spline shaft ends and 1 ⅜” Ø, and hubs vary in B, C, and D dimensions. The adapters can also be used on the intermediate cardans of the implements and for that, there are round and hexagon hole hubs.