iFlight 4 Pair(4CW+4CCW) M5 Aluminium Flanged Nylon Insert Hex Self Lock Nuts with M8 M10 Propeller Quick Release Driver High quality aluminium, surface anodic oxidation treatment, enables higher hardness and longer user life contain a flange with non slip basis negating the need for a washer, prevent the prop fly out ideal replacement for prop mounts on your motors quick release tool easy to carry and use when you assemble the prop with nylon nut screw, one side is M8, another side is M10 4 pair, 4 PCS CW M5 nuts, 4 PCS CCW M5 nuts