Otis Technology 12 GA Bore Brush - 2 Pack Dual Color. 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. Specifications for Otis Technology Bore Brush Pack - 2 Pack: Manufacturer: Otis Technology Fabric/Material: Bronze Nylon Length: 2 in Color: Dual-Color Quantity: 2 Condition: New Features of Otis Technology Bore Brush Pack Otis caliber-specific brushes have the size indicated on the stem ensuring you grab the right brush every time. Package Contents: Otis Technology Bore Brush Pack - 2 Pack Otis Technology FG-512-NB: 12 GA Bore Brush - 2 Pack Dual Color