The N9961B from Keysight Technologies is a RF Spectrum Analyzer with Frequency DC to 44 GHz, Real Time Bandwidth 120 MHz, DANL -163 dBm, Amplitude Flatness ±0.2 dB(Amplitude), Third Order Intercept(TOI) 13 dBm. Tags: USB / Computer Controlled, Analyzer with Screen. More details for N9961B can be seen below.