I now have a print in place version of this thing. Thing:1544351

Keychain holder for 3 SD Micro cards.
Clearances are for ABS, but it probably works well in PLA too. I didn't want mine melting if I left my keys in a hot car :-)
I didn't like the supports generated by my slicer so I've included the manual supports that I used to print mine if you want to use them.
I've been printing them at .2mm layers. I can't get it to complete at .1, it always pops off.
You'll have to do a little trimming with an X-acto knife on the joint, and then I recommend exercising it with some applied pinching force at the joint to smooth it out.
It latches very tight (I didn't want it coming undone and loosing my SD cards). If you want to loosen the latching force just trim down the latching numbs with a razor or some sand paper.