Bushings, sometimes called plain bearings, sleeve bearings, or linear sleeve bearings, are installed between a rotating drive shaft and a housing to help secure the shaft in place and reduce vibration to extend the working life of hubs and shafts. Keyless bushings have a smooth, round bore without a keyway or set screw, allowing them to be used in applications that require the direction of shaft rotation to change. Reducing bushings allow tools with smaller shafts to be used on larger bores. Quick detachable (QD) bushings have a split along one side that eases fitting on shafts of varying diameter. Tapered bushings have a keyway and are installed by pressing the bushing into the bore.