I have this Rapidwinder that i bought for a project that didn't happened, so it is in mint- condition ready to use on a M4-2, M4-P, M6, M6TTL, M7, MP and MP-3, you can use it also in a m3 and a m4 but modification is required.
same, would love one for my M6, but the Motor M came with the body and I can't justify that much money on something that essentially does the same thing (obviate the need to take eye away from camera for winding, I'm left eyed.)