Hoppe's boresnake Viper, everything you love about the boresnake plus better cleaning and superior strength. Features: - Brass weight on the pull cord is stamped with size - 50% more brush cleaning power than the boresnake - cone-shaped bore guide on the leading end - nylon cord attached directly to the bronze scrubbing brush - lubrication zone specifications: - fits: rifles - caliber: M-16, .22 - .225 calibers.