Diff output shaft seal for Cooper "S" and early automatic gearboxes where a Hardy Spicer style axle coupling was used. Be sure to get two new seals for the center bolt (WC-22A1566).
 
If your Mini has a flange with studs and generic u-joints then this is what you are looking for. If you have a flange with a larger rubber or plastic style coupler yoke held in by U bolts, or you have a pot joint (inner CV joint with a rubber boot), then you need WC-ADU5738. 
 
Sold individually.