Hirobo HI2507002 M4.0 E-ring Retaining Clips 10pcs  [HI2507002]

M4.0 E-ring — shaft retention solution

This Hirobo E-ring is an RC-scale retaining clip made to sit in M4.0 shaft grooves, supplied as a pack of 10pcs for routine maintenance and part replacement. It functions as a compact mechanical stop to hold gears, bearings or linkages in place on shafts used in model helicopters and similar hobby models.

Fitting is simple: the E-ring seats into the shaft groove and secures axial components. Inspect the shaft groove for burrs or debris before fitting and confirm the ring fully engages the groove to avoid slippage under load. Its role during setup and tuning is to keep consistent axial positioning so drivetrain alignment and bearing preload remain stable.

Sold as a low-cost consumable, these rings are intended for periodic replacement when refurbishing drive assemblies. Keep spare rings available when working on small drive trains, linkage stacks, or any assembly that depends on a groove-mounted retaining clip.