I needed a breakout board to access all the [Teensy](https://www.pjrc.com/teensy/teensy31.html) 3 and 3.1 pins, and I needed a board to plug Arduino shields with the Teensy. This board is not "Teensy" small but has a lot of space to design many circuits. All the Teensy pins from #1 to #33, VBAT, Program, A14/DAC or Reset on Teensy 3.0 are connected.
Finally there is a lot of space left open for prototyping.
First I ordered a few boards for myself, and found them very useful to convert the unique breadboard prototypes I have for many projects around the house into more permanent installations.
I thought this device could be a good candidate to experiment with Tindie, so I started a shop for it and will report about this adventure in e-commerce when I have a bit more feedback. There are a lot more details about this board in Tindie.