Daniel Defense Barrel Nut

 
Specialized Armament barrel nut wrench - DD RIS II.
 
 
Wrench DD2 in action.
 
 
One of Two
 
Many hours of Design, Engineering, Fabrication & Machining.
This is what a $1000, hand-crafted, tool-steel, proto-type looks like,
after professional TIG welding, multi-part heat treating, and phosphate plating.