for two years I used the apc 12.25X3.75 on my os.46 it was a hugh improvement for 3d over eveything else available. about 9 months ago I tried a 12X4 zinger - this prop is a hugh improvement over apc. it is much lighter, does not cavitate while hovering, has a nice wide smooth power band right around hover - there is another prop es brand from europe that might be even better 13x5 is lighter yet, seems to pull harder, the larger diameter might produce a better giro helping hovering. I will try one and report back.