Body size: 9" x 9" x 4" Material: 409 Stainless Steel Inlet/Outlet size is "inside diameter" Bi-Directional Our Race Venom series mufflers have the same patent pending internal hourglass design as the Venom and Widowmaker mufflers – producing that signature crisp, clean and aggressive Black Widow tone – without a harsh drone sound. All Race Venom mufflers are quality-welded, made out of brushed stainless steel and backed by our Limited Lifetime Warranty.