We used this vibration-dampening U-joint at the column end to help isolate the driver from the road. In a flatfender with skinny stock springs and crappy California roads, every little bit helps. The end of the column is a 1-inch DD shaft, while the new steering shaft is a 3⁄4-inch DD shaft. Not a problem, no string of adapters here. One part reduces vibration and adapts from one size to the next.