Minor remake of this well thought out, rugged PCB holder.
Over the year or so of printing & using the original, I have slightly adapted the design by adding a piece of 5mm bungee cord and a bungee cord spring stopper to tension the clamping force of the PCB within the jaws. The stopper can be adjusted for a firm hold. I have added 2 holes to the sliding side STL file to allow the shock cord to be threaded back on it's self and a simple knot to secure it. (not shown in the pictures) The tension side STL has just one centre hole allowing the the bungee cord to be tensioned via the spring stopper.
The second remodel was to the jaws themselves, they now have a 2mm lip on the under side of the slot, allowing the PCB to be inserted into the jaws more easily . Adding a small elastic band into each jaw slot and wrapping around the jaw spigot stops the PCB sliding within the jaws. The jaw retainers were added just to stop the jaws popping out when not in use.
Supports needed for both the Jaws and the Jaw Retainers.

All credit goes to Tthaler for this outstanding design.

For this PCB holder you will need :

Below easily purchased on AliExpress
5 pcs M3 square nuts (DIN 562), do take note, must be DIN 562 nuts or they don’t fit.
5 pcs M3×10 socket head screws (ISO 4762),
2 pcs LM 10 UU linear bearings.
2 pcs 10 mm linear guides.

Below purchased from Ebay.
2 pcs no4 screws for jaw retainers.
300mm of 5mm bungee cord.
1 pcs small single hole shock cord stopper.
2pcs small thin elastic bands.

Note.. If the jaw slots are a little tight, an easy way to open them out to the correct size is to use a piece of cut PCB board. The rough cut edge can be used to saw the slot without opening it up too much.

Printed in PETG.