The Gemini R’s cavity’s size is 65mm x 160mm deep (2.5” x 6.3”). Maximum temperature differences are ±1°C in the range of 100°C to 500°C. The Gemini R is capable of accepting blackbody fixed points to achieve the highest level of a radiation measurement possible. Typical fixed-point uncertainties are ±0.25°C. Gallium, indium, tin and zinc cells are available.