This is the Tekin Gen4 17.5 Spec-R Sensored Brushless Motor.

Tekin’s SPEC-R brushless motors are engineered for award-winning performance. Utilizing the best materials available we redesigned the SPEC-R to cut weight while reducing resistance, resulting in a purebred Spec racing machine. On Road or Off, the SPEC-R handles all situations, providing smooth power and control across all RPMs when you need it. The SPEC-R is competition performance with the speed you need to win. Pair with an RS PRO Black Edition for the ultimate in SPEC Racing Equipment.

The GEN4 motor line is a completely new ground-up design. We put in the design and test time so you can reduce your lap times. The new stator is precision stamped and pressed, increasing efficiency and reducing resistance. Our motors are hand-wound with high purity copper wire and machined from 6061-T6 aluminum. Completely tunable with optional rotors and re-buildable, the new GEN4 SPEC-R motor is a premium performance power plant for the serious racer.

Features:
60 Degrees Adjustable Timing Advance
SPEC Racing Specific Design
CNC Machined 6061-T6 Billet Aluminum Heat Sink Can
Neodymium Sintered Magnet
Precision Engineered for Maximum Energy Conversion
High Purity Copper Windings Maximize Conductivity
Low Resistance, High Power Solder Tabs
Sensored System Ready
Anodized End-bell Plates Maximize Corrosion and Wear Resistance
High RPM Precision Bearings
Oversized Front Bearing
Rebuild-able Design
Solder-less Sensor PCB Replacement
Legal in Major Race Governing Bodies
ROAR Approved

Specifications:
Input Voltage: 1-2S LiPo
Weight: 5.1oz / 145g
Shaft Size: 3.18mm / 1/8”
Motor Length: 50.25mm / 1.978”
Motor Diameter: 35.85mm / 1.40”
Max Operating Temperature: 180F / 82C
Bearing Dimensions: Front 4x13x5mm / Rear 1/8x38/5/32”
Rotor Size: 17.5T: 12.5mm BLUE
Rebuildable: Yes