The Isotech Oberon 426 high temperature furnace is designed for use with aluminum, silver or copper fixed point cells and can also be used as for comparison calibration. With a temperature range of 450 to 1100°C (1832°F) and ±0.05°C stability, the Oberon offers ideal conditions for the creation and maintenance of slim ITS-90 cells. The cavity size is 50mm (diameter) by 300mm (depth). Additionally, the Isotech Oberon 426 can be used with blackbody fixed point cells.

Water supply and waste connections are provided for a water supply of 0.5 to 1 liter per minute. The working fluid is permanently and safely sealed within the plasma-arc-welded enclosure. This is not recommended for use without cooling above 700°C. The furnace core features a stress-free isothermal heat pipe which provides a very low thermal gradient along the core working length. The inner wall is not subject to thermal expansion stresses from the outer wall before the heat pipe reaches conduction temperature.