Primary gear thrust washers are made in varying sizes to take up the play when driving a MINI.
Standard gap size should be between 3-6 thou. See DAM6487, DAM6488, DAM6489, DAM6490 and DAM6492 for alternatives. This type is for the 1275cc crankshaft only which has a raised step for the primary gear to sit on. Thrust washer 0.114-116”(2.89-2.94mm).
The measurement is taken as plus or minus one to the size hence the two thou tolerance on each part number.