Cleaning brushes have machined aluminum components that don't react with ammonia-based solvents like brass parts sometimes do. Won't produce blue-green stains on your patches that can be misinterpreted as "false positive" indications of copper fouling, so you'll know when your bore really is copper-free. Similar in hardness to brass, Copper Eliminator parts won't scratch the bore or damage the muzzle, and they'll stand up to hard use. Nylon bristles wound around an aluminum core and male-threaded aluminum coupling are completely brass-free to eliminate false-positive blue-green indications of copper fouling that can occur when using ammonia-based sol Mfg: Dewey SPECS: Nylon bristles, aluminum core and ferrule. Thread patterns indicated in table. Sold in 3- and 12-paks.