Effectively cleans 30-06 cal., 30-30 cal., .308 cal., 7.62mm, and 300 Win. Mag. firearms in one pass. Heat resistant (up to 700Á) synthetic fibers (NomexÂ) outer layer is the same material used in protective gear used by firefighters, race car drivers, and the U.S. military. This material won't melt in the barrel. Rigid, durable materials trap fouling better than nylon products. Nomex acts as both a brush to loosen and a patch to capture fouling products. Molded rubberized core keeps the Nomex cleaning surface pressed against the bore - ensuring an aggressive 360Á clean. 10" aggressive cleaning surface Helix shape engages the rifling through the length of the barrel. Coated solid brass threaded ends won't scratch or damage bore. Safe for all firearms. 8-32 standard threads are compatible with all Otis cleaning components. Safe obstruction removal for jammed cases and other blockages. For proper cleaning insert the longer, narrower end in the chamber and feed to the muzzle. Pull through from Breech-to-Muzzle. Repeat as needed. Use only for caliber specified. Hang packaged.