I already disassembled this one, but the third card was so elegantly fastened I had to keep the picture.



That card slot cover kept the top card firmly in place! I could take the rig in my hands and shake it in any orientation, and it wouldn't budge.

The ziptie on the middle card actually kept it as one piece. The fan shroud and some plastic shrapnel fell off when I took the card from another rig, but fixing that was easy!