This is the Novak SS8.5 Pro Brushless Electric Motor.
Specifically designed for cars and trucks, ROAR legal.

FEATURES: Sensor based design for excellent starting torque, continuous
synchronization, low-speed driveability, consistent brakes and
thermal protection
Provides approximately 20% longer run-times than brushed motors
One-piece design neodymium magnets provide high power and great
reliability
Nickel plated sintered neodymium rotor
User-replaceable rotor, front end bell/bearing, and rear bearing
Convenient solder tab system for easy wire replacement
Thermal Overload Protection (when used with a Novak brushless ESC)
Non-removable color timing ring
Lightweight ribbed aluminum end bells
120 day limited warranty

INCLUDES: Novak SS8.5 Pro Brushless Electric Motor

REQUIRES: Electronic Speed Control for brushless motors

SPECS:    Turns: 8.5
Design: Sensor-based
Motor Size: 540 Size: 2.08" L x 1.41" D (52.8 x 35.8mm)
Weight: 6.61 oz. (187 grams)
Input Voltage: 4-7 cells (1.2V/cell or 4.8-8.4 total volts)
Magnet: Nickel-plated, Sintered, high-strength Neodymium
Watts: 280
KV (unloaded): 5000
Shaft Diameter: 0.125" 3.2mm (accepts all existing pinion gears)
Front Bearing Size: 1/2 x 3/16" (12.7 x 4.8mm)
Protection: Thermal