1977-DP - 

Test Kit, Digital Field Meter, 20 kV Voltage Rating, LCD Display

Thermally conductive material used between power transistors and heat sinks to optimize heat dissipation and reduce operating temperature.
A heat conductive material used to coat the bases of power transistors as they are connected to heat sinks. The grease is heat conductive and will draw the heat away from the transistor allowing it to run cooler.