When ordering a right angle flex connector, it is important to know that there are options for top and bottom contact locations. The reason both configurations are required is that flex circuits are usually manufactured with only one  side of the cable prepared with exposed conductive material.  In the illustration, you can see the upper board accepts the flex conductors on the top side of the flex circuit while the lower board accepts the flex conductors on the bottom. Having both options available simplifies designs and insures that the mating contacts will be in the proper location to mate with the flex circuit.