I got the cheapest possible one - it's going to be covered in stickers anyway - which came to US$60 with the deluxe package. Honestly, I wasn't thrilled at the price but they're the only ones doing precision cut covers - and it does cover the top, bottom, and wrist-rest.

Here's how it looks out of the box:

And here is is fitted:

There are decent instructions on how to apply but it's fairly simple. The sticker can easily be pealed off if you need to re-apply it. Which is just as well, because some of the thinner strands need to be reapplied several times. Weirdly there are stickers which cover the fan holes. Not sure what that's about!

It applies really smoothly and air-bubbles are easy to push out.

There's also a wrist-rest cover:

Again, slightly fiddly to get it lined up perfectly. There's also a trackpad cover sticker. Personally, I prefer the way my finger glides across the bare surface, so I left it off.

The top cover is a blank rectangle. It grips tightly enough that the embossed logo subtly shows through:

The material is 3M™ Controltac™ which has a fairly neutral texture, smooth finish, and a consistent colour. The reverse is sticky but doesn't leave a tacky residue.

There are some great looking skins at dbrand - but if you're happy with a plain colour, they're about $25 + shipping. I got the deluxe version and a pack of silly stickers to get up to $60 for free international shipping. A little expensive, but the cuts are precise, the material sticky enough, and it gives your laptop a bit of personality.

Right, time for more stickers!

I want to add an NFC reader to it.

So, step one was to find an NFC circuit board which worked with the hardware and was relatively small.

Enter the ACM1252U-Z2. It works perfectly with Linux. It has a USB-Micro socket - but a USB-C OTG cable allowed it to work with the Framework.

It is about as small as they come - but will it fit?

Thanks to Alexey for sending me some 3D printed samples of the Framework expansion plugs, I was able to make a bit of progress.

The board is slim enough in height and width to fit into to the casing:

But it will stick out rather alarmingly:

It's useful to have the antenna that far out - but I'm worried about bumping it.

What about under the casing of the main laptop? There are two spacer units which can be removed, and there is access to the internal USB connectors under the numpad.

Will it fit? The answer, again, is… oooh! Just about!

If the trackpad was moved left, there'd be plenty of room horizontally.

It will still need something sturdy covering it - and that will need to be transparent to RF.

So here are my next thoughts:

1. Can I (or someone else) desolder the USB-Micro plug and solder on a USB-C OTG plug?
2. Is having a protruding expansion going to be annoying or dangerous?
3. How hard would it be to replace the spacer and wire directly into the vacant USB pins under the numpad?

If you have answers to these questions - please drop a comment in the box.

For example, Framework sells an official HDMI card and Ethernet card:

But the community have built their own SD card expansion pack as well as 3D printed snack drawers:

Brilliant!

I have an NFC-only authentication token which I want to use when I log in with my laptop. I currently have a USB-C NFC reader which I could use, but it is a bit big and bulky.

Is it possible to fit an U2F capable NFC reader into a FrameWork expansion slot?

Size of expansion cards

This was a bit tricky to find. Based on this GitHub page, I think the maximum internal dimensions of a circuit board are about 26mm x 29.7mm. Tight!

According to this video from Framework about the cards shows the maximum size of the physical cards.

All the cards use a USB-C connector which sits proud of the card itself.

Potential Hardware

First up is this tiny NFC reader. It is designed for phones, and costs about a fiver. The dimensions look like it would might fit if the plastic shell were removed. But the description says:

Output 4/7 bytes of chip serial number, UID only

So no good for doing U2F. But it does at least show that reading an NFC card ought to be possible in a small form factor.

There are component USB-C readers

That one would easily fit - but the description says it is for reading only. So I don't think it can send the cryptographic challenges necessary.

Then there's the ACM1252U-Z2 - Small NFC Reader Module which costs about £60.

It is a much more capable reader. It uses micro-USB rather than USB-C, which isn't insurmountable using a flexible male-male cable. What about the dimensions?

Certainly thin enough! But about twice as long as we need. Could we chop off the end? What's on the other side of that empty space?

Ah! A honking great antenna. If it could be bent at 90°, it would "only" stick up 2.5cm. Which would be ugly, but not disastrous.

Then there is the ACR122T which is in thumb-drive format.

That might work. The antenna is probably in the bulbous end. The official schematics don't give much clue.

But if we look in the FCC Database there are some internal photos!

Ignoring the USB jack, the board is about 50mm long. That would leave about 2cm sticking out of the side of the laptop. Which isn't too bad. The width is within what we need. There's even an updated version with a slightly different spec.

I could buy an A-to-C converter which would add unwanted extra length. I wonder how hard it is to unsolder the connector and mount a USB-C one?

This video makes it look relatively simple.

But, given the weirdness with resistors, it might be easier to use an OTG Shim.

I could rip that apart and solder it on to the board. Or perhaps just solder on a USB-C OTG board. Maybe?

I guess it is time to buy some components and try not to break them! If you have any advice or suggestions, please let me know!