Here's the official smak-dab:
I thought I had read (but can't find now) that it was a metal clip covered in plastic but it might be all plastic/nylon.
What I did discover with MY version (the office clip) is that it needs to be near the center (spine of the case) or it is hard to grab the light and pull it out.
Amazon sells or so does the manufacturer - shipping is about the same cost as the $3-$4 clip!
https://smak-dab.com/Home_Page_L1P1.php