HF03 is a heat flux sensor commonly used in fire testing. It is designed for short (< 10 min) monitoring and measurement in high flux environments in the heat flux range up to 10 x 10³ W/m². LI19 displays the measured heat flux. Once programmed with the sensitivity of the connected sensor, the display will show the actual value of the heat flux in W/m². LI19 is programmed via its PC user interface. It communicates over USB. We recommend downloading the latest software. LI19 may also be used to store measured data. LI19 is battery powered, using 2 x AA-type batteries. Fresh batteries allow 50 days of operation. HF03-LI19 is not rated for EEx (potentially explosive) environments; nevertheless it is often admitted, because the instrument operates on 3 VDC only.