The BTCU26004 from Bore Tech features the Cu 2 Copper - a cleaner that is biodegradable, non-hazardous, and free of any odor or ammonia. Its primary function is to extract all copper fouling in the bore of your firearm.This high-quality cleaner includes a rust-preventative component that provides a protective shield and conditions the bore of your firearm. It has proven results on steel, stainless steel, and lined barrels, making it an ideal choice for these materials.