Sidewinder S4 retractable tether
 

I purchased one of these items for my rangefinder. I used it for about 3 weeks and took it back to the store. Take my advice and don't buy one of these. First off, if this item was used too quickly it would make a ratcheting sound. (used slowly it was quiet enough). Next, I followed the installation instructions to a "T" by cleaning the area with the supplied alcohol wipe, applying the shrink wrap bands and attaching the safety lanyard.
Using it in the tree stand attached to my belt it was a bit uncomfortable especially with my safety harness but nothing I couldn't live with.
But what really forced me to take it back was I was still hunting some rough country. Steep, rocky, climbing over logs, rocks etc. After about 2 miles or so I happen to reach down to find my rangefinder hanging on my belt. The adhesive broke loose and the piece came out of the 2 shrink wrap bands. The only thing that saved me from loosing an expensive rangefinder was the safety lanyard.

Thanks for the review/warning. These things have been paired with a bino harness on Camofire a lot lately, and been thinking about it.