Bore Tech understands the need for premium quality nylon brushes, which is why they have constructed these “double wound” Proof-Positive Nylon Brushes that feature superior construction and materials. These brushes have twice as many bristles as competing brands to double the scrubbing action and shorten the cleaning process. Features oversized bristles for added strength, and non-brass cores and couplers that prevent the appearance of copper fouling remaining in your bores. The .17 and .20 caliber rifle brushes are 1' shorter in length to reduce the force needed to push the brush through and prevent barrel damage. For best results use Proof-Positive Nylon Brushes with fast acting copper cleaners like Bore Tech’s Eliminator and CU+2 Copper Remover.