It can be separated and be taken axial loading. The single direction bearing only can takes axial loading in one direction, however, the double can takes axial loading in two directions, it can support alternating axial loading in either direction. During the working time, it must be preload. They are used in lathe centers, automobiles, clutches, reducer etc. The double directions angular contact the thrust ball bearing are suitable for machine tools, however, the single one can be used to take ball screws.