Finding materials exactly appropriate for making anything of any kind is a bit more difficult in small towns than in larger cities. Anyway, sometimes necessity really is the mother of at least something close to invention. The tethers below make use of dress shoe shoe laces and electric clamp-on spade lugs butchered a bit. I have used a shoelace like this for several years with my cellphone. Cord was still good, but my twisted wire and shrink insulation was getting a bit ragged. Both that tether or cord and the one I made for the Nikon in a previous post were both also just a bit short. The images below give an idea of what resulted.
I cut the clamp part of the spade lugs off and opened them a bit with a knife to get the doubled shoelace into them. The crimp part of the lug had to be filed a bit to get rid of jagged edges. Then once lace was in the crimp ends, the were crimped and squeezed with a plier. I tested these by pulling hard on them, but they seemed to hold well. This all wasted some time, and I am sure could have been done for less cost were such crimp ends were available for cords and string. Anyway, it seems so far to have worked and is at least a bit neat in appearance at least. I put the lace end through the hole I had made previously in the lenscap with a 1/16 inch drill bit. It had to be enlarged slightly. Once through the hole, I cut the plastic end off the lace and tied a knot in the cord so it could not pull out of the lens cap. Pays to do some measuring with cheap string before cutting up a shoelace.
The crimped metal was also from an electrical spade lug. The clip is from an old ID name tag. One like this clipped to my shirt collar has prevented this phone from being dumped out of my shirt pocket and nto waste oil and toilet water more than once.
I hope you can find easier solutions than these, but if you can't, I hope these gizmo how-to methods can be useful to you.
***Stay tuned for much less practical ideas--- Doug Wiken