The Isotech ITS-90 Isothermal Towers combine the fixed point cell and heat pipe (or siphon) to produce ideal realizations for calibrating standard thermometers. This tower utilizes a heated block on top of the heat siphon/cell to fully compensate for the immersion characteristics of the unit under test.

Designed for laboratory use, the Isotech ITS-90 Isothermal Towers have been evaluated against and meet all the requirements of CCT/2000-13. An added benefit of this unit is that because the cell, apparatus and immersion compensator are a single entity, the performance eliminates ambiguity unlike systems where the cell and apparatus are often separated during intercomparison.