OMPHOBBY M4 Helicopter Main Rotor Hub(Black)OSHM4008B Sale! from 2174 /per Qty. Add to Cart This is a replacement main rotor hub for the OMPHOBBY M4 Helicopters Contents Main Rotor Hub-1socket cap screw M2.5x14-1M2.5Nylon locknut-1 Qty available:2 SKU:OSHM4008B