this is just a little sling for the moded BJ-2 Combat Knife and Dsman's assault knife. Its a snug fit and the knife will most likely not fall out while running or jumping. If it doesn't work for you let me know. It might be the sling or the knife.
Step 1: Part 1
This is the side of the sling that straps onto the belt you wear.
Step 2: Part 2
this is the other side of the sling.
Step 3: Putting Part 1 and 2 Together
Follow the pics.