Backtrack 2 True Dual Tire Truer With Diamond Drums Brushless DC motor: New Diamond Drums added to this model that will never wear out! It features ball bearings and a built in micrometer measuring system, no more bolts required to set and repeat sizes! Dual drums allow truing a pair of tires at the same time. Powerful brushless Motor does not require an external power supply to operate. Axle included is for 3/32" Wheels and can be switched out with any 1/8" Axle for 1/8" wheels. Has enough clearance to true 1-5/16" drag tires. A 2mm option will be available soon for faster scale cars.