The CT ratio 1M miniaturized fiber optics ratio thermometer from Optris is designed to measure temperatures from 700°C up to 1800°C of metals, metal oxides, ceramic materials and materials in the semi-conductor industry under harsh environments. This infrared thermometer is insensitive to certain dust and partially obstructed targets. It uses a 2 channel measurement principle with 2 built in infrared detection channels with different measuring wavelengths to produce 2 independent electrical signals, which are dependent on the infrared radiation emitted from the target and signal components. Similar signals in both channels are eliminated. The measured temperature of the object depends on the signal and emissivity ratio.