@fwafwow - You could go that route, but that particular coil is way too bulky and rigid for me, and if/when the silicone stretch-case ages/cracks/breaks, you’ll have to ante up $20 again.
A cheaper DIY option is to purchase about 9’ of 1/8” shock cord (aka bungee cord) and fashion your own for under $3.00.
I’ve made it a habit that whenever I place an order for anything at Eastern Woods Outdoors, I always add about 20’ of shock cord to the order because I always seem to find unplanned uses for it. DanO only charges 25 cents per foot for the stuff, so it’s really cheap and it works great for fashioning retention cords for your range finder, GPS, binos, game calls, cell phone, etc.
Here’s how I fashion it for my cell phone retention cord. The measurements apply to a large format iPhone, which is about 6.25” x 3.25” with the case I’m currently using. Of course you can fashion a similar rig for any size rectangular device, you’ll just have to experiment with it until you get the fit you want…