The Isotech GEMINI 4857/550 is a high-temperature blackbody calibrator that provides a stable and accurate temperature reference for calibrating infrared thermometers. With a temperature range of 30°C to 550°C (1022°F) and an emissivity of 0.995, it is ideal for calibrating Raytek ST, MX, and CI Series thermometers. The GEMINI 4857/550 includes an external reference probe and accepts fixed point cells, ensuring accurate and traceable temperature measurements.