The Tekin Gen4 Spec-R Sensored Brushless Motor has been engineered for performance. Utilizing the best materials available the SPEC-R has been redesigned to cut weight and reduce resistance, resulting in a purebred Spec racing machine. On Road or Off, the SPEC-R handles all disciplines, providing smooth power and control across the full RPM range. The SPEC-R is competition performance with the speed you need to win. The GEN4 motor line features a redesigned, precision stamped and pressed stator to increase efficiency and reduce resistance. The stators are hand-wound with high purity copper wire and machined from 6061-T6 aluminum. The motors can be tuned with optional rotors and are re-buildable, making the GEN4 SPEC-R motor a premium performance power plant designed 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 - 25.5T / 21.5T / 17.5T / 13.5T / 10.5T / 6.5T Weight: 5.1oz / 145g Shaft Dimensions: 3.18mm (1/8") x 15.3mm Motor Diameter: 35.85mm / 1.40" Motor Length: 50.25mm / 1.978" Max Operating Temperature: 180°F / 82°C Bearing Dimensions: Front: 4x13x5mm Rear: 1/8x3/8x5/32" Rotor Size: 12.3mm BLACK - 25.5T, 12.5mm BLUE - 21.5T / 17.5T / 13.5T / 10.5T Rebuildable: Yes