Magneto Rotor, Single Prong by RICHARD GOODE AEROBATICS, for Auto Advance / Retard magnetos
New production rotors for Auto Advance / Retard timing M9-Series Magnetos. ( M9, M9-25, M9-35, ) and Huosai CD-5 Magnetos
The one prong is a giveaway that this rotor needs to be used with aircraft without a Shower of Sparks system.
If your magneto has fixed timing ( M9-F) you will need the double prong rotor - this component is unsuitable.