Tethys Instruments is a dynamic team of engineers developing innovative solutions around UV and IR spectroscopy. The team has multidisciplinary skills in optics, physics, chemistry, mechanics, electronics and software to cover all the fields necessary to develop and produce cutting-edge online analysers. A long experince on manufacturing makes the production efficient and flexible with a high level of quality. Several innovative technologies have been developed internally to achieve a high level of reliability and performance for online monitoring such as xenon flash lamp that gives an unparalleled lamp life-time; concave gratings coupled to 2048 pixels charge-coupled devices (CCD) for high resolution and sensitivity, high speed digital signal processor (DSP) that supports sophisticated algorithms and gives a high selectivity on the data-analysis. Great efforts have been put on an user-friendly interface to ease the start up and the use of the analysers. Software updates and configuration backup/restore are done by USB keys on all our products. A colour touch screen display interface allows the user to easily navigate through a number of screens that are used to set and check all of the operating conditions of the instrument.