M4.0 Retaining Ring Pack 10 — Hirobo HI2507002  [HI2507002]

Secure shaft stop for M4.0 grooves

The Hirobo E-ring is intended for use in M4.0 shaft grooves and is packaged as ten retaining clips for regular servicing and part swaps. It acts as a simple axial stop to retain gears, bearings or linkages on shafts in model helicopters and other hobby builds.

To install, press the ring into the shaft groove so it seats evenly and prevents axial movement. Always check the groove for dirt or sharp edges before fitting and verify the ring is fully engaged to reduce the risk of the clip popping out under load. Proper use helps preserve drivetrain alignment and bearing preload during setup.

These rings are economical replacement items and are typically swapped out during repairs or rebuilds. Keep extras on hand when working on compact drive systems, control linkages, or any assembly relying on a groove-mounted clip.