Heavy duty needle roller type coupling with plastic ends. The very early Minis used the rubber joint drive couplings
GCD101 to eliminate harshness from being transmitted to the passenger compartment. Over the years the rubber will separate from the metal sleeves and allow the driveshaft to rotate out of concentricity. Not only can this cause vibration, but it can also allow it to hit either the tranny case or more often, the exhaust pipe. These are 16mm narrower at 92mm from side to side than a rubber coupling which can help when fitting a LCB exhaust manifold.
The rubber coupling alternative made by Mini Spares has superior nylon cups with needle bearings. U bolts should be tightened to 8-10lbf.ft-do not over tighten.
A car set (both sides) comes complete with new U-bolts, & nuts.