Ah, I see, the release video uses a two-blade, the one I saw was with a 3-blade, they must have flown with different props at different times in the video. That 2-blade might be a 10x45 (not a slow-fly) or maybe even a 10x6, the new radial motor might be able to handle that much of a prop

.
EDIT: Looking at
@DamoRC ’s tests over
here , the new radial 2218 will handle a 10x6, so that’s probably what they used (on 3s, not sure what they used on 4s).