This is a 2.54mm protoboard for the Flipper Zero in a unique backpack-style formfactor!
Check out the Github Repo for a full explanation, source files, build guide, as well as a collection of other designs in the same formfactor! The repo also includes printable case options as well as a FreeCAD project for creating your own cases.
Breaking out all GPIO of the Flipper it allows you to create your own designs for it, as well as adapting existing dev boards to this new formfactor. Soldering IS required for this, as the boards come unassembled, and obiously require you to put your own design on it.
The kit consists of the 2 interlocking boards as well as the pin headers to connect them to your flipper. Soldering is obiously required to assemble the two boards at a right angle as seen in the build guide.
It's designed to fit your Flipper wearing the silicon sleeve, but it also works without the sleeve.
The entire project is designed with open source tools, allowing further modification and forking of the project. All source files are published in the Github Repo using FreeCAD as well as KiCad.