This is the Xerun V10 G2 8.5 Turn Modified Brushless Motor, recommended for 1/10 on-road, and off-road vehicles.

Xerun V10 G2 Motors
Specifically designed for extreme running in top 1/10 and 1/12 scale competition racing, the V10 G2 series motors and are compliant with ROAR, IFMAR, BRCA and JMRCA rules. They featuring the perfect combination of high quality materials, exquisite craftsmanship and cutting edge technology, the V10 G2 series provide the extra advantage all professional racers are looking for with minimal maintenance required.

Features:

Specifications:
kV: 4050

Resistance: 0.0163 Ohm
Current w/o Load: 3.2A
Max Output Power(w): 360
Current @ Max Output Power: 90
A
Can Diameter: 36mm
Can Length: 52.5mm
Shaft Diameter: 3.175mm
Shaft Length: 14.6mm
Weight: 178g
Rotor: V10-
Φ5-12.3