Datasheet

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, giving you a full
strip of connected pads.
You'll need to solder on the female headers and/or stacking headers
however you like, the Doubler comes as a mini kit!
Check out our range of Feather boards here.
 PCB Dimensions: 50.9mm x 47mm x 1.6mm / 2" x 1.85" x 0.06"
 Weight: 6.7g