The .17 Caliber Copper Eliminator Male Jag is designed for effective cleaning of .17 caliber firearms with 5-40 threading for secure attachment to cleaning rods..17 Cal. 5-40 Thread Male JagCopper eliminator design for removing copper foulingMale threading (5-40) for compatibility with standard cleaning rodsPrecision-engineered for .17 caliber bore cleaningEssential for maintaining accuracy and performance in .17 caliber rifles by effectively removing copper buildup from the barrel bore.