-YFB thrust needle bearings are composed of a set of tray ring gaskets combined with retainer with roll bearings( needles ).The stand leads and holds many rolling elements( only very tiny differences among the elements in the same group ) .The thrust needle   bearings or thrust-cylindrical roller bearings can support the bearings with the axial directional load and so they can be used as the bearings with good rigidity and minimum axial occupied spaces.If the surface of the adjacent parts can be used as a tray for the rolling needles and the holding stand assembly,configuration of bearings can be very compacted .In case this disposition can not be realized,As series tray assembly should be recommended when the support space is big enough so that a small axial cross sectional altitude can be achieved . Same effectiveness can be ensured in different cases when combined with the relatively thicker ring gaskets of  LS,GS,WS,ZS series.The applicable gaskets series of AS,LS,GS,WS,ZS are optional and will be ordered sparately by the buyers' demand.