I added a 16L3B Turk's Head knot to this Cold Steel Trail Master sheath.
I started with a 50 foot length of paracord and could have added a fifth pass to use up most of that, but stopped at four passes. That used right at 38 feet of cord.
It's just a different way to carry some extra cordage. If I needed to use some of that cord, I could unwork part or all of the knot. It comes apart a lot faster than it took to make it.
I took the remaining 12 feet, doubled it up, then tied it into a hangman's noose/coil knot on the leg strap part of the sheath. This can also be worn around the wrist as a paracord bracelet if you size it right. You just have to make sure the coils are tight so they don't get snagged and pulled loose...