Iosso Products AR-15 Brush Kit4 Brush PackBlue. 223 Bore Brush. They are sized to close tolerance for precision cleaning. They are made out of a distinctive blue fiber which is thick stiff and holds it's shape well. This allows for back and forth action unlike traditional brass and bronze type brushes. They may be used several times before becoming worn. You may also purchase these brushes separately. Specifications for Iosso Products AR-15 Brush Kit: Manufacturer: Iosso Products Gun Type: Rifle Features of Iosso Products AR-15 Brush Kit Includes Upper Receiver Brush Bolt Carrier Brush Chamber Brush and .223 Bore Brush Sized to close tolerance for precision cleaning Distinctive blue fiber bristles Brushes may be used several times before becoming worn Holds shape well Package Contents: Iosso Products AR-15 Brush Kit Iosso Products 19115: AR-15 Brush Kit4 Brush PackBlue