The purpose of a Ring, as a metal fastener, is to hold components onto a shaft or in a housing or bore when installed, typically in a groove. Rings can include Retaining Rings (internal or external), Snap Rings, Circlips, or E-Rings. When installing an External Retaining Ring, ensure the sharp side of the ring, as opposed to the rounded side, is facing towards the direction of thrust for a more secure fit within the groove. Retaining Rings may require special pliers for removal or installation.