Allows you to add that 3rd or 4th receiver to your dual lnb. Has off air input(built in diplexer).This switch will work with any dual lnb,standard dbs dish. Either Dish Network's Dish 300 or any standard Directv Dish. It is not designed for multiple satellite dishes like dish network's Dish 500. For the dish 500 you will need a SW-44 or SW-64 Switch.(Actual switch shipped may be slightly different from that shown,and may be a different brand depending on stock on hand, but will be similar quality.)