






Using your DeWalt DCF840E1 impact driver is a breeze. First, charge the 20V MAX* DEWALT POWERSTACK™ Compact Battery using the included charger. Once charged, insert the battery into the driver. To drive screws or fasteners, select the appropriate bit and insert it into the 1/4 - inch drive. Hold the driver firmly and use the variable - speed trigger to control the speed. You can adjust the speed according to the task at hand. When working in low - light areas, turn on the 3 - LED work light to improve visibility. Remember, the maximum initial battery voltage is 20 volts, but the nominal voltage is 18. For maintenance, keep the driver clean and free of debris. After use, store the driver in the included kit bag. If the battery gets hot during use, let it cool down before recharging. Also, make sure to use the battery only with DEWALT® 20V MAX power tools and chargers for best results.