It's an active duty variant. There were three of them made, they had a recurved blade, a serrated top (wich wasnt really sharp), and a modified handle. The handle modificaiton was the best part, because it lowered the hump on the back of the handle, wich had always felt akward to me since it shifted your grip to far back when you gripped hard.
It was sharpened down to have a polished 21 degree edge, and a 24 degree secondary bevel.
Unfortunately I still found that the choil was a still a huge problem on a knife that was that short. I tried cutting a wadded up ball of plastic in half at work, and just couldnt do it quickly even though the knife sailed through the stuff. I just wanted to be able to let the stuff run along my fist and hit the blade so I didn't have to think about placing my cuts.
This was for someone else

I wish they were mine... I felt bad about them though. The 4" PBF was the only one that I felt really good about how it turned out. they were all sharpened down to 24 degrees (21 would have made the bevel go almost to the top of the main grind) with a 27ish secondary bevel. the tips were around 35 degree's, and they still almost complely overtuke the main grind. These things are built like TANKS.
I felt bad because I couldnt quite get them to be totally mirror polished, wich really came down to me being so tired, and my hands so sore after 30 some od straight hours of working on them that I was making stupid mistakes and not being as careful as I should have been. The mirror polishing required a really light hand over multiple grinds, and i could have done it by just freehanding it, but I didn't take the time...
The handle wraps are what I really felt bad about. The 4" PBF's turks head knot came out perfect, it was tight, even and nice looking. I couldnt get the rest of them to even out correctly, there was always at least 3 places where the knot was too tight around one of the brites (sp?) to get it to go down into the weave and flatten out. But, to their credit - they are TIGHT. Tighter then any paracord weave you've probably ever handled. You could hammer fist slam the butt of those knives onto concrete all day and the weave wouldn't shift noticably. They are as tight as the 7 strand paracord could take without being cut by my pliars....