Otis Technology Canister POP - Blue Nylon AP Brushes 150 108541. This is due to the superior construction and engineered features incorporated into the brush such as a precision thread with no weak undercut. These brushes have a Tufcor proprietary core wire that is corrosive resistant has a tighter twist for better bristle retention and can be used with all firearm cleaning chemicals. Otis premium bore brushes also have twice the fill as other brushes the stem is cold welded to the core and the brushes are filled to the end. Each brush features the size stamped on the stem and color-coded core wire to easily identify the brush size; this means that you will never clean your gun with the wrong brush. Comes 150 Per Canister Package Contents: Otis Technology Canister POP - Blue Nylon AP Brushes 150 Otis Technology 108541: Canister POP - Blue Nylon AP Brushes 150