Using your DeWalt Digital Torque Wrench is easy. First, insert the batteries provided in the package. Then, select the appropriate measurement unit (ft./lb., in/lb., or Nm) using the button on the wrench. When using it, make sure the wrench is properly attached to the fastener. You can read the torque value clearly on the backlit LED screen. As for maintenance, keep the wrench clean and dry. After use, store it in the provided case to protect it from damage. Avoid dropping the wrench or exposing it to extreme temperatures. If the batteries run out, replace them with the same type of batteries. And always make sure the rubber - bumper head is in good condition for maximum durability.