Walker 21598 Exhaust Muffler Spun-Locked Heads Help Resist Ruptures Due To Backfires Bridge Construction For Structural Strength And A Long Service Life Durable Internal Partitions For Greater Interior Structural Stability And A Long Service Life The Inner Shell And Outer Cover Lockseams Are Positioned 180 Degree Apart For Maximum Durability Strong, OE-Style Interior Spot Welds Help Improve Structural Stability And Increase Durability