Hirobo HI2521134 Collar 3 x 6 x 12.25 RC helicopter collar  [HI2521134]

Helicopter Collar for Shaft Alignment

This RC-scale collar is a general-purpose replacement part listed under Hirobo helicopter general parts. The HI2521134 designation identifies the 3 x 6 x 12.25 collar size used where axial location and concentric alignment of rotating components matter.

In practice the collar functions as an axial stop and alignment sleeve inside transmission or rotor assemblies. During maintenance or part replacement verify mating dimensions, clean contact surfaces, slide the collar into position on the shaft or in the housing, and secure using the model's original retaining method. After installation check runout and axial play as part of routine tuning to ensure smooth operation.