This LNB is used for getting signal from the 119, 110, and 129 satellites. It is internally switched, no external switches required. When installed on a Dish 1000.2 dish, this is capable of bringing in HD channels from the 129, something a 121 Superdish cannot do. You can only use this LNB on a Dish 1000.2 dish, as it won't physically fit on any other dish. Use this LNB if you want to use 3 single-tuner receivers, like a 301, 311, etc., or if you want to hook up 3 dual-tuner receivers, like a 322, 625, 622, etc.