Prefixes are used to identify components of a bearing and are usually then followed by the designation of the complete bearing, or to avoid confusion with other bearing designations. For example they are used in front of designations for tapered roller bearings according to a system described in ANSI/ABMA Standard 19 for (predominantly) inch bearings.

AR-Ball or roller and cage assembly
Motor encoder unit BMB series
Motor encoder unit BMD series
Motor encoder unit BMO series
Bearing, designated by a drawing number
Stainless steel, inch dimensions
E2.SKF Energy Efficient bearings
GSHousing washer
Oil sealed bearing unit
IR-Inner ring of radial bearing
KCylindrical roller and cage thrust assembly
K-Inner ring with roller and cage assembly (cone) or outer ring (cup) of inch tapered roller bearing belonging to an ABMA standard series
LSeparate inner or outer ring of a separable bearing
OR-Outer ring of radial bearing
  1. Inner or outer ring with roller (and cage) assembly of a separable bearing
  2. Support roller without an inner ring
  3. Bearing without an inner ring
Sealed bearing
Bearing with NitroMax steel rings and bearing grade silicon nitride Si3N4 balls (hybrid bearing)
WStainless steel, metric dimensions
WFDeep groove ball bearing of stainless steel with external flange on outer ring
WSShaft washer
ZEBearing with SensorMount® feature
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