The CellaTemp® PA 41 is a digital two-colour pyrometer with fibre optics for the measurement of temperatures in the range 700 to 3000 °C. The two-colour pyrometer is equipped with a separate optical measuring head and a light guide. The light guide and measuring head are insensitive to interference from electromagnetic radiation and can be used in ambient temperatures up to 250 °C without cooling. The variant with a separate optical measuring head is particularly advantageous in confined spaces.