LONN-200 series products are medium and low temperature popular thermometers, which adopt the latest invention of our company A series of novel optical components such as optical field converters, photoelectric multi-parameter differential amplifiers, optical filter isolation, and mode stabilizers can determine the temperature of the measured object by measuring the wavelength of the object's radiation wave. In short, it uses the most advanced digital sensing technology to measure the wavelength or wavenumber of the radiation wave of the heating body to represent the temperature value of the measured object.