The device includes a fused-quartz tube matched pair. The Inner tube fits inside an outer tube which is held by a support clamp assembly, that also supports the measuring device. Specially prepared specimens are placed at the bottom of the outer quartz tube with the inner resting on it and the measuring device in contact with the inner tube to indicate variations in length of the sample with change of temperature.

A temperature controlled bath is also available, to control the temperature of the test samples. The bath is made of stainless steel, double walled insulated with single dilatometer capacity holder. The programmable PID temperature controller controls heat and cool supplies, it includes an electric rod heater and a cryogenic valve to bring nitrogen into the bath.