RETAINING RING

Fits:

Big Twin Models (1989–2006): Commonly used as the retaining ring for the transmission mainshaft bearing and the trap door bearing. This covers various Dyna, Softail, and Touring models within these production years. 

Sportster Models (1991–2021 & beyond): Frequently fits the clutch access/inspection cover (often called the chain/clutch inspection cover) on Evolution Sportster models. 

Buell Models (1995–2002): Used in various primary/transmission assemblies

OEM retaining ring or snap ring. It is primarily designed for transmission applications, most commonly securing the transmission trap door bearing and mainshaft bearing on Big Twins, as well as the clutch inspection/access cover on Sportsters