OTIS BORE BRUSH PACK .270 CAL. 2 PK. Otis brushes have a proprietary Tufcor core wire that is corrosive-resistant with a tighter twist for better bristle retention and brush life. These brushes clean 6.8mm, .270 cal, 7mm firearms, are 2� long, and fit 8-32 threads. Includes one nylon brush and one bronze brush.