A dual lnb sees one ORBITAL satellite LOCATION as there could be more than one satellite at each location but some people refer each orbital location such as 119 for example as a satellite. These were found on the first dishes that came out which were later named Dish 300. The Dish 500 (to see two orbital satellite locations) is where the twins were first introduced to replace the first version that had two duals paired with an sw-21 switch. Later they came out with a Dish 500 twin with the two duals and switch built in together. The first Dish 1000 (to see three orbital satellite locations) they came out used a DPP twin along with a dual DP lnb with the switch being built into the DPP twin lnb. Later they created the current 1000.2 dish with all three lnb's built in together.