Advanced level brushless motor from Solink which includes a High-Low RPM speed switch (low RPM is about 20% slower than fast RPM).  Addtionally the motor features a uni-directional bearing what prevents reverse rotation.  In an ideal build you could remove the ARL, however I still recommend fitting it.

The external shell is CNC machined from aluminium.  Uses a D Type pinion gear with a hardness rating of HRC35-38.
The motor tower OD is 7.9 and an inner hole diameter of 3.2

These motors have great heat efficiency, reliability and performance from either 7.4v or 11.1v.  According to Solink you can use AB and Precock, and state their motors are fully compatible with all ETU's.

Solink Motor Comparison

IMPORTANT
1. Do not power the motor with the cables reversed.  Always check this.
2. Solink state that this is the most ETU compatible motor on the market and can be used with AB should you need to, no reported issues currently.  
3. As with all motors if you get a gearbox lock-up, don't keep your finger on the trigger trigger.  Use common sense.
4. If changing the pinion yourself do not force it on, do not whack with a hammer! Too much force will damage the rear bearing or controller.  There's some good guides on YT on how to remove pinion gears on brushless motors.