For more than a decade Castle has been providing award winning brushless sensorless motors to R/C enthusiasts worldwide. In response to overwhelming requests by our customers, we have brought technological advancements together that will deliver unprecedented performance in our new sensory motor line. Why sensored? drivers in all applications demand clean starts when coming off the line. Crawler fans require high-precision low speed control and torque for climbing, racers need precision and predictability, and dragsters don't have a millisecond to spare. To achieve all of these performance demands and more, we have integrated rotor position sensor technology with our improved high power and high efficiency motor design. Through the use of our sensors, the position of the rotor is always known by the ESC. This eliminates the possibility of encountering cogging or inconsistency during startup. Users will experience precise throttle control and buttery smooth starts plus the raw power and longer run times that our highly efficient motors produce. Our improved 4-pole 12-slot design boasts exceptional efficiency and produces less heat. Quietsense technology shields the sensors from magnetic field noise generated from the motor coils and keeps your motor and ESC in sync at all times. Use of a Flux shield in conjunction with secondary sense magnets delivers even higher precision and more efficient startups. Our optimized design eliminates the need for mechanical timing adjustments. Our sensor alignment method delivers uniform timing and torque in both directions, automatically. Rebuildable design allows users to replace front-end bell/bearing assembly or rotor/shaft assembly. Roar standard sensor port and labeled connections. Updated modern and sleek design; looks as cool as it performs. You will reap the benefits of longer run times on one battery and a cooler running motor that can be pushed harder. We take overpowering seriously.