The VHBU-VSBU-VHBUR-VSBUR-K4 from WORK Microwave is a Block Upconverter with Gain 35 dB, Gain Flatness ±0.5 to 1 dB, Harmonics -40 dBc, Image Rejection 80 dB, Impedance 50 Ohms. Tags: Rack Mount. More details for VHBU-VSBU-VHBUR-VSBUR-K4 can be seen below.