The KH3938B from Beijing KeHuan Century EMC Technology is a RF Spectrum Analyzer with Frequency 9 kHz to 1 GHz, Frequency Resolution 30 Hz to 10 kHz, Attenuation Range 0 to 79 dB, Spurious 40 dB(Response), AC Supply 220 VAC. Tags: Analyzer with Screen, USB / Computer Controlled. More details for KH3938B can be seen below.