The N9933B from Keysight Technologies is a RF Spectrum Analyzer with Frequency 5 KHz to 4 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 N9933B can be seen below.