Designed for use with our #499 Prop Balancer. Accurately balances quadcopter props and allows you to eliminate vibration from unbalanced props. Works with all 5MM threaded props like DJI Phantom and more. Perfectly "true" shaft with clockwise threaded end and a counter-clockwise threaded end.; Balance 5MM quadcopter or drone props;Clockwise threads on one end and counter clockwise threads on the other end;Perfectly "true" shaft to show any imperfection in prop; Du-Bro Products 5mm Quadcopter Prop Balancer Shaft