Thrust ball bearings are classified into those with flat seats or aligning seats depending on the shape of the outer ring seat (housing washer). They can sustain axial loads but no radial loads. For Single-Direction Thrust Ball Bearings, pressed steel cages and machined brass cages are usually used The cages in Double- Direction Thrust Ball Bearings are the same as those in Single-Direction Thrust Ball Bearings of the same diameter series.Available in two designs: single direction and double direction. Single direction design includes two rings, referred to as shaft and housing washers and a single ball and cage assembly. Double direction design, on the other hand, includes three washers and two ball and cage assemblies. The ball and cage assemblies of the double direction type are separated by the shaft washer.