Cartridges are factory assembled sets of Spindle Bearings, preloaded and greased, complete with applicable seals, ready for installation. This reduces parts count, as well as manufacturing and assembly times, by combining Covers, Seals and Distance Rings into an easily installed, integrated assembly. Simply install the unit into a cylindrical bore in the applicable housing and insert the shaft. The bearings arrangement is possible various layouts: As DB up to QBC with distance ring to enlarge the supporting width.