Check the listing for details. HP 5350B Microwave Freq Counter , 10Hz -20 GHz, Oven Reference. Condition: Used. Listed at 545.00 USD. Operation tested and verified Cosmetically unit is very clean Service and operations manual included on CD Unit shipped in double boxed double walled box Internal Reference Oven HP 5350B: Features: * 10 Hz to 20 GHz * 11-digit display * Measures frequency, period, period average, ratio, totalize, and time interval * Built-in microprocessors provide math functions, including measurement scaling and offset * Automatic amplitude discrimination measures the frequency of the highest amplitude signal in a multi-signal environment * Sensitivity to -40 dBm ensures accurate measurement of low-energy signals * Fast acquisition time (60 ms in automatic, fast acquisition tracking mode; 20 ms in manual mode). 120 measurements per second over HP-IB.