The motor mount hole size is M3 and the shaft diameter is M5,This brushless motor can support QAV210 X220 QAV250 FPV Racing Quadcopter. Using N52 tile magnet, to ensure motor efficiency and performance.Using high-strength aviation aluminum, high-precision CNC machining process. Using the latest self-locking screw anti-shedding design, instead of the traditional card spring, more secure and reliable. 5mm hollow steel shaft design, plus hard treatment, resistant to falling fried. Low center of gravity design, more stable; centrifugal fan design, better heat dissipation, greater thrust.