Factory 4.1 muffler available in natural titanium or blue anodized titanium with titanium end caps The lightest mufflers available Superior power and performance - horsepower improved throughout the rpm range Feature exclusive proprietary Chamber Core technology Factory Forward Engineering centralizes mass, improves handling Made from premium quality American materials Customize with performance tuning inserts and spark arrestor module Meet AMA sound requirements on most models; inserts available for others. MUFFLER ALUM FACT 4.1 CRF