REAL AVID Bore-Max® Speed Brush® Multi-Cal PackBore Max Speed Brush Multi Cal Pack CLEAN BORES FASTER This Bore Max Speed Brush pack includes 10 popular pistol and rifle calibers in one convenient storage case. Bore Max Speed Brushes have twice the bristle density of standard brushes for maximum scrubbing power and faster results. Stiff, nickel plated phosphor bronze bristles reduce chemical breakdown from solvents and extend the life of the brush.