The SJ-ST-3000-4000-15-2 from A-Info is a RF Variable Attenuator with Frequency 3 to 4 GHz, Attenuation Range 0 to 15 dB, Attenuation Step 0.5 dB, Attenuation Accuracy ±0.5 dB, Insertion Loss 4 dB. Tags: Module with Connectors, Digital. More details for SJ-ST-3000-4000-15-2 can be seen below.