Drone/Quadcopter Prop Balancer & Shafts \(3mm\) \(For DJI Phantom 4\) Part No: 3388. The Du-Bro Drone/Quadcopter prop balancer`s aluminum wheels turn virtually friction free for precision accuracy. The Du-Bro Tru-Spin Prop Balancer will balance drone props of all sizes and weights. 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.Specially designed balancing shaft with left and right hand threads. For Drone/Quadcopter Props. Balancing shaft is made of CNC machined aircraft aluminum for a precision balance. Some very popular drone models such as the DJI Phantom 4 include unique prop hub that will not work with traditional balancers. Du-Bro has a solution for these props with our centerless ground Friction-Fit prop balancing shafts that works with the popular #499 or #3396 Tru-Spin Prop Balancer.