Woodward Double Universal Splined Shaft.

Double Universal Joints Double U-joints neatly solve problems that cannot be dealt with any other way. However, unlike a single u-joint, a double joint does not make a stable connection between two shafts because it essentially adds a shaft. Therefore the two shafts to be joined by a double u-joint must both be supported individually or the connection will wobble. A direct connection to a fixed component (such as a steering rack or gearbox) will support that end, while the other end will require a rod end or other bearing.  UAD3 UAD4 UAD5 The 20-tooth spline in the Woodward 201 U-joint is timed with respect to the bearing axis, so any two joints assembled back-to-back on a 20-spline shaft will have parallel axes and will be in phase for maximum efficiency. Although the maximum operating angle of a double U-joint is theoretically twice that of a single joint, it is always best to keep misalignment of the steering shaft to a minimum. Even where they are not absolutely necessary, double U-joints provide smoother rotation than a single joint used at the same operating angle.

UADS-3 1.75" Overall Length.
UADS-4 2.75" Overall Length.
UADS-5 3.75" Overall Length.