Smaller sizes are available with either a flat seat surface on the housing washer or a sphered seat surface

Smaller sizes are available with either a flat seat surface on the housing washer  or a sphered seat surface . Bearings with a sphered housing washer can be used together with a sphered seat washer  to compensate for misalignment between the support surface in the housing and the shaft.

Thrust ball bearings 51104 with small size and low price