This mounts on your Ketch board to hold the ID tag in a CPR tournament.

UPDATE: There is a "large hole" version added. The first version works with a Zip tie for a hinge. I also added some "D" shaped hinge pins that you can print flat and use a flame or soldering iron (or heated screwdriver tip...) to weld the outside edges. I would still prefer the zip tie or original with #8 or 4mm screw

There are 2 versions of the "plaque" part which supports the tag. One is framed and fits my particular zip-loc style ID holder, and the other is "flat" / universal. The universal one is green in the rendering.

It was designed to use a typical US hardware store 8-32 screw (#8 with 32 threads per inch) at 2" long. The hole might be snug enough with your printer to not use a nut. The threads should secure in the plastic. BUT surprise! I threw a zip tie in mine for giggles and it is perfect, holding the open position at ~50-55 degree max.
This zip tie is light duty (40 lbs) and measures 3.5mm width if that helps... a #6 machine screw and nylon locknut or #8 drywall screw will work too. The hinge hole is 4mm.. maybe a chopstick? It will be cool to see a build using something different. But the zip tie is pretty simple. The hole is 4.1 mm. There is a Larger hole version laid out for 5.5mm also

Click here for my measuring board holder

Make all of these you want for your buddies, no commercial re-sale, please.

These are oriented to maximize strength ready to lay on your bed with no supports.

I print them at 0.2mm, 20% infill (Grid is good), 3 perimeters and 4 Bottom and Top layers using 0.3 or 0.4 nozzles in PETG. (245/70)

Almost forgot... the "Retainers" are just clips that you can see used in the picture of mine. They snap into the frame to hold the ID tag secure. If you are using Velcro on the flat plaque, no need to make the retainers!