We can supply you gear box for cordless impact drills.Can be used for 10.8-18V cordless drills.Have both impact funtion and drill funtionIf any interest, please feel free to let me know.Specifications: Reduction ratio: 50/15Maximum torque stiffness / toughness £ (Nm):30--13No load speed (rpm):0-380/1300Pounding force (bpm):21000Gear box settings(No): 22+1Gear box size(mm):10Maximum drilling diameter in wood (mm): 29Maximum drilling diameter in steel (mm):10Maximum drilling diameter in stone (mm):10Maximum diameter of screw (mm): 8