This is the FeatherWing Doubler - a prototyping add-on and more for all Feather boards. This is similar to our FeatherWing Proto except there are two! The magic of the Doubler comes when stacking a Feather and another board on top of the Doubler so you can work with both boards simultaneously side-by-side! In addition to the board the Doubler comes with:
The Doubler, like the Proto, has a duplicate breakout for each pin on a Feather, as well as a bunch of plain grid proto holes. Also, the two sets of pins are cross connected and for GND and 3.3V, we give you a full strip of connected pads.