This is a standard milspec part. The Delta Ring assembly usually consists of 3 pieces that attaches to the rear of the barrel and clip on to the barrel nut. To the new AR builder, this is not always apparent. The barrel nut must be installed before installing a gas block, whether low profile or a traditional A-frame front sight base. Many replacement barrels with FSBs come with the barrel nut, but not the three-piece Delta Ring assembly.
This set comes from Stag Arms, which has been a rifle and parts maker for decades. You can count on Stag to provide solid mil-spec parts.
This product is the delta ring assembly and the barrel nut.
