The SM 6121 Starter EGT (Epicyclic Gear Train) Gear Set is a high-precision internal component kit specifically designed for Lucas-style (L. Type) reduction starter motors. This set of three planetary gears is engineered to transfer high torque from the armature to the drive pinion, providing the mechanical advantage necessary for smooth and efficient engine cranking. Manufactured from high-grade, heat-treated alloy steel, these gears are built to withstand the intense rotational stress and friction found in modern reduction-type starters.