4" 2:1 Fat Shot System, Chrome

12-17 Dyna

• Famous proven tunable disc based performance.
• Add or subtract discs to optimize power and sound
• 1.75" primaries flow into 2.5" true collector for huge torque gains
• 3.5" muffler body flares out to 4"
• 2.5" performance core with 'pillow pack' insulation
• Supplied with discs, closed end cap and trim ring
• Include detailed instructions and all necessary mounting hardware
• Add 4” discs to increase horsepower, exhaust tone and flow
• Subtract 4” discs to reduce sound and increase low-end torque