This is the Great Planes ElectriFly 6mm prop adapter motor shaft collet 5/16-24 output shaft. Prop adapter to fit standard size propellers onto a 6mm motor shaft.
Features: Large shaft size for Brushless (or Brushed) motors with smooth (non-threaded) shafts
Requires: Tightening the prop nut to compress the prop adapter onto the motor shaft
Total length: 1.72 (44mm)
Diameter of drive washer and prop washer: 1.2 (30mm)