Adafruit featherwing add ons for all feather boards adafruit 2890 the adafruit featherwing doubler prototyping add ons let you work on a feather main board and another board at the same time side by side the boards are supplied with stacking headers so you could also plug the doubler into a feather main board and work on two featherwings boards this is a board youre going to want in your toolbox because theres guaranteed to be a situation when you want to get at the middle board of a sta