[Christ]

Nah, it means that you get 2x the torque output per area of motor. The efficiency number is what you're going to want to pay attention to when determining the amount of power it will make, and how long it will last on a given pack voltage/rating.

Basically, most electric motors have an armature and a housing. One has magnets, the other has windings (very simply put.) This design takes the armature and puts a splined disc on it (or two, or three, or four) so that it almost resembles a Wankel Internal Combustion Engine, i.e. the "rotors" are tied to the shaft by a splined interconnection (possibly splined, there are other ways, as well) (For the purpose of the explanation, we'll stick with splined, though). On each side of the rotor, there is a set of magnets. What you end up with is something like this:

|:||:||:||:||:||:|

Where : = rotor (with magnets) and | = discs with windings, or vice versa (flip windings and magnets, but then you'd have to add brushes.)