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

E-ring design and intended use

The Hirobo E-ring is an RC-scale retaining clip made for M4.0 shaft grooves, sold in packs of ten for maintenance and replacement tasks. It provides a compact mechanical stop to secure gears, bearings or linkage parts on shafts in model helicopters and related hobby models.

Installation is direct: the clip snaps into the shaft groove and restrains axial movement. Before fitting, clean the groove and remove any burs or debris, then confirm the clip fully engages the groove to avoid slipping under operational loads. Correct positioning ensures drivetrain geometry and bearing preload remain consistent.

As an affordable consumable, these rings are commonly replaced during rebuilds or repairs. Keep spare rings available when servicing small-scale transmissions, linkage stacks, or any assembly relying on groove-mounted retention.