Female header is like the duct tape of electronics. It's great for connecting things together, soldering to perf-boards, sockets for wires or break-away header, etc. We go through these real fast, and thought that given how handy they are, we'd offer them in a pack of five!
Each pack contains red white 20-pin 0.1" pitch female headers. These are a little extra special in that the plastic holding the pins together is made of red plastic instead of classic black.
You can cut these down to different sizes fairly easily with diagonal cutters to cut in between pins.