Skip it and buy a quality wrench. - Precision Reflex Armalite Combo Barrel Nut Wrench

I've purchased better tools at harbour freight. Plasma cut with pins welded in place, very poorly made (pins not close to straight) and not well finished. Did not fit my 20 tooth dpms g2 and i doubt would fit anything else given the poor placement of the pins. Gordon Ramsey would ask if they actually test these on real barrel nuts before shipping. I ended up cutting a proper wrench on a waterjet.