This Recommendation specifies the metrological characteristics required for resistance thermometers having one or more sensing elements made of platinum, copper or nickel, designed for use in measuring temperatures in the range from – 200 °C to + 850 °C, or in a part of this range. This Recommendation also sets out the methods and general specifications of the equipment for verifying resistance thermometers. It applies neither to instruments for the measurement of resistance, nor to indicating instruments. Values of temperatures in this Recommendation correspond to the International Temperature Scale of 1990 (ITS-90) [1].