IOSSO AR15 Bolt Carrier Brushes w/ Stud 2PK These unique brushes are superior because they are sized to tolerance for precision cleaning. They are made of a blue Nyflex fiber, which is a stiff, thick fiber that holds its shape well and allows for back and forth action unlike traditional brass and bronze type brushes. They may be used several times before becoming worn. The brushes are wound tightly so there is more cleaning area per inch. The shank is a solid construction, sized to fit 8/32 cleaning rods. When used with IOSSO Bore Cleaner and IOSSO Gun Oil, it will remove nasty carbon burn and all other fouling, including copper and lead. Directions for use: First, apply the Eliminator Gun Oil to a patch and run it through to remove any loose residue. Second, apply IOSSO Bore Cleaner to a brush and clean one or more times as needed. Follow with clean dry patches until one comes clean. Third, moisten one or two patches with the Eliminator Gun Oil, run through, then follow with a clean dry patch. This methods allows for cleaning to be done in fifteen minutes or less with no smell, and no running or splattering of fluids. Upon inspection, the bore will be free of all fouling.