GoolRC M1 5mm 11T 12T 13T 14T 15T Pinion Motor Gear Combo Set for 1/8 RC Car Brushed Brushless Motor For 5mm shaft diameter 1/8 RC car brushless brushed motor Hard anodized on the gear surface Rust-proof treatment on the surface of gears The gears are milled by precisely Tanwai milling machine A M4 set screw (12.9 level) has been added to each pinion gear