Double ends allow for large surface scrubbing on one end and precision cleaning with the smaller end. Includes brushes with different bristle material for varying levels of aggressiveness when cleaning: nylon, blue nylon and bronze. The nylon brushes are the least aggressive, meet Mil. Spec. and are safe for everyday use. Recommended for use on virtually any surface including wood surfaces.Blue Nylon Brush features stiff bristles that allow for a more aggressive clean.Bronze brush gives you the ability to scrub hard to reach places where carbon, powder, and copper residue build up.Recommended for cleaning the area around the firing pin and perfect for metal surfaces that require more aggressive scrubbing action.