KKmoon Blade Propeller Balancer for 250 450 500 600 700 RC Helicopter Multirotor Airplane Full use of carbon fiber and aluminum CNC machining, applies to all the main rotor mounting holes for the 2-5MM diameterAll of the main rotor, the overall 2MM Carbon metal frame structure, anchor using franc bearing design, standard.Level viewer, easy to adjust the main rotor balance. While additionally equipped with a magnetic balancer, can be more accurate detection of the main rotor static and dynamic balance.