Hirobo HI2521104 Collar 3 X 6 X 12.5S Replacement for RC Helicopters  [HI2521104]

RC Helicopter Collar Size 3 x 6 x 12.5S

This item is an RC helicopter replacement identified as Hirobo HI2521104 and is intended where a compact collar is needed on rotating shafts or linkages. The part marker 3 x 6 x 12.5S helps match the collar to existing shafts and housings on your model.

Before fitting, check the shaft and bore for scoring or dirt, remove any contaminants, then position the collar and fasten it using the retaining system original to your airframe. Always confirm clearance and alignment before flying because small position changes can influence tail and rotor behavior.

During maintenance and tuning, collars are used for exact axial placement and to reduce lateral movement in rotating parts. Periodic verification of collar fitment supports consistent rotor head and tail performance and helps maintain trim stability.