Rubber U-joint for yoke-type driveshafts. These are the only new supply available except for QL5000 alternative.
The very early Minis used the rubber U-joint drive couplings to eliminate harshness 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 standard replacements 108mm wide with u bolts and nuts for one side only.
QL5000 are 92mm wide which helps out when trying to fit an LCB.