It looks very close, but i think its the sling posted above. If you look at the pics on Bravocompanyusa, one of them looks just like the one in the pic.
It was hard to tell from the pic you posted (here’s a hot link) to the pic, but since the picture was from an article about NSW weapons, I figured it was the Dieter. Still could be wrong, as I think you’ll find that an assortment of slings have been used by the SEALs.
Still, the Dieter’s has seen widespread use with the Mk18. Here it is in 2pt configuration.
it’s a cqd sling that has been chopped up so you can just attach it to a carabeener or someother method on your kit. lot of guys do this. hope that helps.