The prop balancer's aluminum wheels turn virtually friction free for precision accuracy. The DU-BRO® Tru-Spin Prop Balancer will balance model airplane props of all sizes and weights, drone and quadcopter props, boat props, spinners, car wheels, helicopter rotor heads, jet fans, fly wheels, etc. Each balancer comes complete with easy to follow assembly and prop balancing instructions. A truly precision instrument built for the modeler who expects the very best.