These two Female Headers alone are, well, lonely. But pair them with any of Adafruit's Feather boards and you're in business!
What do they do? They get soldered on either side of the Feather board. Now you can plug in FeatherWings to add more capability to your portable project. Unlike the Feather Stacking Headers, they aren't designed to 'stack', but they're more compact.
Note: Comes with one 12-pin and one 16-pin header, Feathers not included