This is a Traxxas 20 turn Stinger electric motor. The Stinger motor is a mild modified motor that gives you a good balance of speed and run time, depending on how you have your car set-up and what kind of batteries you are using.
A "20-turn" single (which is the designation of the Stinger motor), indicates that a single thickness of wire is wound 20 times around the armature of the electric motor. The less times the wire is wound; the faster the motor will go. The thicknesses of wire around the armature determines how much torque the motor puts out. So, a 20-turn double would provide more torque than the 20-turn single. Remember, though, that a modified motor must be geared properly in order to achieve its maximum performance and may also eat up your battery causing you to have shorter run times.