The GenRad 1404 Series standard capacitors are the standard of choice in metrology labs, and still used today by standards bodies around the world. These capacitors have been designed as primary reference standards of capacitance with which working standards can be compared.
In combination with an accurately known external resistor, the GenRad 1404 standard capacitors becomes a standard of dissipation factor
All critical parts of the plate assembly are made of Invar for stability and low temperature coefficient. After heat cycling and adjustment, the assembly is mounted in a heavy brass container, which, after evacuation, is filled with dry nitrogen under pressure slightly above atmospheric and sealed. The container is mounted on an aluminum panel and protected by an outer aluminum case. Each capacitor is subjected to a series of temperature cycles to determine hysteresis and temperature coefficients and to stabilize the capacitance
Current list price from IET Labs $5889 with 8-20 week delivery time!