This is the lightest, and strongest, most compact emergency rescue/back-up rope there is. I'm amazed That it isn't marketed more as such. I was impressed with how nicely it made and kept knots. But is very difficult/tedious to secure the rope ends once cut. Top of the line kit, too bad the price matches, but you get what you pay for, especially if its your life. 4000lbs is way more than enough strength, but if it was any smaller in diameter it would be too hard to rappel with.