I bought and built a Null2 from this link: https://www.null2.co.uk/ However, I wanted to use this battery: https://www.adafruit.com/product/328 instead of the smaller one that fits in the original case. So, I got the original files from the guy who designed and sells the Null2 and made these modifications: Larger battery space, hand grips, letters on the buttons(where applicable), a better cover for the speaker holes, and the words “start” and “select” for those buttons. I had a great time soldering and building the Null2 and I highly suggest you pick one up if you like to emulate old games. From my experience, it can handle most retro games from the GBA down, plus its handheld! Which beats emulating on a PC any day!

NOTE: Even if you aren't using the print profile, and you're just printing the raw .stl files, I suggest printing the front cover face down on a smooth plate(not a textured PEI plate) also, back prints best with the outside facing up(the part you hold), but the supports can be a pain, so I used a lot of support blockers and then just relied on bridging, the inside doesn't need to look good, you wont see it.