Using your DeWalt DCF900P2 Impact Wrench is easy. First, insert a fully - charged 20V MAX* XR® battery into the tool. Then, choose the appropriate mode on the 4 - mode push button switch according to your task. If you're worried about overtightening, use the PRECISION WRENCH(TM) mode. To work in the dark, turn on the on - tool LED work light. When you're done, remove the battery. For maintenance, keep the tool clean. Wipe it down after each use. Also, check the battery regularly. If you notice any signs of wear, replace it. When not in use, store the tool in the provided kit bag to protect it from damage. Make sure to charge the battery in a cool, dry place using the DCB115 charger.