The N9935B from Keysight Technologies is a RF Spectrum Analyzer with Frequency 5 KHz to 9 GHz, DANL -155 dBm, Attenuation Range 30 dB, Amplitude Flatness ±0.5 dB, Third Order Intercept(TOI) 15 dBm. Tags: Analyzer with Screen. More details for N9935B can be seen below.