Installing solar panels can result in a missed opportunity if they're not positioned optimally to catch the radiation from the sun. Similarly to a TV installer using a signal meter, you can use this device to find optimum locations on a rooftop (or wherever you're installing them) to help ensure they'll be efficient and generate as much of their rated power possible for your location. Expressed as either W/m2 (Watts per square metre), or BTU/ft2 (British thermal units per square foot). Measurement up to 1999W/m2, or 634BTU/ft2. With data hold and high accuracy, you can get rapid readings on the huge LCD. Includes carry case.