DSTV Universal Twin LNB (Low Noise Block downconverter) for satellite TV dishes. An LNB is the small device mounted at the front of a satellite dish (on the LNB arm). It receives the weak microwave signals from the satellite (like from DStv, MultiChoice, or other satellite providers), amplifies them, and converts them down to a lower frequency so they can travel through coaxial cables to your decoder/receiver without much loss.