The Muvi X-Drone 10" self-tightening propellers are made with hard-wearing plastic giving you stable flight conditions for stable video shooting and photography. Fully compatible with the Muvi X-Drone series the propellers automatically self-tighten when the motors are started to ensure that they do not come loose during flight and to prevent the user from over-tightening. Includes two clockwise and two anti-clockwise propellers that prevent you from installing on the wrong motor arm to ensure a safe and successful flight.