Otis bore brush pack 17hmr/.177 wsm/.177 cal airgun brushes are 1" in length, allowing for limited breech cleaning.Otis brushes have a proprietary tufcor core wire that is corrosive-resistant with a tighter twist for better bristle retention and brush life.With twice the fill of other brushes and bristles right to the end, you get superior quality and precision cleaning every time.Two per package- one bronze and one nylon.Thread Pattern: 5-40Quantity: 2 Per PkgBristle Type: Bronze/NylonLength: 1"