This is two versions of a hinged DOPE card, or range card, holder made to fit on the tube of a rifle scope and designed to utilize inexpensive blank PVC ID cards (write on them with water erase pen). One style allows you to simply drop in the card, the other is a basic tab for using velcro on mount and card. The C clamp, for mounting, is designed in two sizes. One for large scope tubes, 34mm in diameter (eg Vortex Venom), the other is 30mm for many other scopes. I strongly recommend you use PETG. at least for the C clamps. I did a lot of testing and found that PLA consistently failed, breaking sooner rather than later. I have yet to have a PETG clamp break. I printed with 100% infill but I imagine anything north of 50% would probably work. If you are concerned about wear, or tightness, on your scope tube, a single wrap of tape will fit under the clamps and address either issue.
The author marked this model as their own original creation.