Here is the answer from our general department: Generally speaking, this single/twin specification is referred to in the sense that it is a single or dual LNB system (or twin LNB), and part of a satellite dish that allows you to tune in more than one set of channels at a time. LNB stands for Low Noise Blocker. This is the component that is pointed at the centre of the dish and picks up the reflected signal and sends it via coaxial cables to your receivers, which means that only one LNB is suitable for one TV and with the dual LNB the user can connect 2 TVs.