The LI-19 Handheld Datalogger & Read-Out is compatible with analog EKO irradiance sensors, including the Class B MS-60 and Class C MS-40 pyranometers, and the MF and HF range of heat flux sensors. Many irradiance and heat flux sensors are read with installed data acquisition systems in the field or laboratory; however, some applications and projects may instead require fast, simple, and accurate measurements using a mobile manual read-out --- the LI-19. Configurable via Windows software, the LI-19 can connect with a PC via USB and, with its internal memory, can be set to store data at regular intervals. The sensitivity value of checked sensors can also be set via the software. The LI-19 is also supplied with a carrying case for additional sensors, USB cables and batteries.