Genuine Makita HY00000659 — Stop Ring (E‑3). A small steel stop ring / circlip designed to retain shafts and internal components in Makita pneumatic nailer assemblies; listed in Makita parts diagrams as "Stop Ring E‑3 (AF635)."

This single, low‑profile ring is the exact replacement part used to secure moving parts inside the AF635 finish nailer and the same stop ring appears in Makita parts lists for several nailer/stapler models (examples include AF635, AN454, AT638A and AN924). It’s sold individually under part number HY00000659 as a genuine Makita spare.

Perfect if you need the original Makita retaining ring to restore proper alignment and safe operation of the nailer’s internal assembly — fit, form and function match the factory part so you don’t have to modify the tool.