Well, I haven't found it yet. But I can tell you the gruapner y531 (smallest my local shop had) doesn't work for brushless, but worked great on the stock bl9. Had to make a new prop shaft adapter to use a 1/8 dog and prop on 2mm shaft. The 31mm was way too much for brushless. Just flips the boat if you give it any decent amount of throttle. I have a few 2 and 3 blade on the way from 26mm to 30.