Balance all model props both Large and Small, Tire and Rotors with the Tru-Spin Prop Balancer by DU-BRO. It is both Precise and Accurate. It comes with specially designed locking cones which securely center and lock props on the balancing shaft. balancing shaft is made of hardened material and is centerless ground for precision balance. The aluminum wheels turn virtually friction free for superior accuracy. Made in the USA.