The Smart-Fit Bore Guide is the ultimate and first-of-its-kind spring-loaded, precision cleaning tool providing worry-free cleaning. The spring-loaded slider locks, providing a secure fitment and ensures a consistent chamber sealing with zero movement when running brushes and patches through your bore. An anodized aluminum tube is designed for lasting durability and the contoured, non-marring, bore-specific tips ensure damage- free, precise fitment on centerfire rifles from .243 – .375 caliber.