For a wide range of use, this model features a total 4- speed change mechanism (2 mechanical speed reduction and 2 electrical speed reduction). Optimal rotation speed and torque can be selected depending on processing materials and drill diameters. The quiet sound in electrical low rotation speed will help to increase working efficiency without disturbing the environment in the neighborhood. User Beefits: 4-speed gearbox with pre-set Hi/Low speeds. Low speed - high torque setting. Ideal for engineering applications. Suitable for mixing applications in low speed. Heavy duty construction. Rear D-handle and side grip for controlled drilling. Slide switches for easy and smooth speed change operation. Heavy-duty industrial chuck. Double Insulated