The following Mini 4WD PRO motors Item 15346 Torque-Tuned Motor PRO, Item 15350 Rev-Tuned Motor PRO, and Item 15351 Atomic-Tuned Motor PRO all come with brass pinions. When you would like to exchange these brass pinions with resin ones, this Pinion Puller will make the job easier. The Pinion Pulley can also be used for the removal of resin pinions.