The earliest Minis had ball bearing rear wheel hubs, but taper rollers were introduced with the Cooper S model and were later used on all (classic) Mini models. Aftermarket; sold per wheel kit, two (2) required per car. The set now includes an integrated spacer built into the inner races, so there will be no separate spacer supplied.
Compared to the ball bearings at the rear of early Minis, the taper roller setup is much easier to remove for regreasing, etc. The old ball bearings were often destroyed in removing the rear hubs.
For MPi classic Minis beginning in about December 1995, see GHK1805.