Suitable for FPV Racing Quadcopter brushless motor (installation diameter 5mm) Feature: Lightweight, non-slip locking more reliable than propeller nuts Kind remind for buyers: CW shaft should use CW screw nuts, CCW shaft should use CCW screw nuts. It has nothing to do with CW or CCW motor, CW motor might use CCW screw nuts. Juts check your motor shaft. CW Lock Nut is silver color,and CCW Lock Nut is black color. 8mm end is suite for most FPV racing motor with M5 screw nuts,like Emax RS2205. Emax MT2204 2206 2208