Hmmmm, I should have been a little more specific.
The original phantom with keyed props use the 2214 model motors, the self tightening prop will need the reversed threaded motor for two of the props . . .
I'm not sure if the reverse threaded motors/kit have the shaft flat spots as the self tightening props wouldn't have that keyway setup (but stock props do).
Original standard phantom - 4xMN2214
or upgrade to 2xMN2214 + 2xMN2214-11
Phantom Vision/(late model phantoms, w/self tightening props)
Must use 2xMN2214 + MN2214-11