Thermistor Mount. High efficiency and good radio frequency (RF) match are characteristic of the 478A Coaxial Thermistor Mount. Used in conjunction with the 432 Power Meter it provides high accuracy even in routine power measurements. The unit is temperature compensated for low drift, even in the presence of thermal shocks, permitting measurement of microwave power as low as one microwatt. Frequency range 10MHz to 10GHz.