Extech dt300 laser distance meter extech dt300 the extech dt300 laser distance meter has a continuous measurement function with min max distance tracking which updates every 0 5 seconds it can measure from 50mm to 50m 2in to 164ft and will automatically calculate area and volume using pythagoras theorem the meter can calculate an indirect measurement given two others supplied with a carrying case and 2 x aaa batteries extech dt300 laser distance meter