Made from 16-gauge 304 grade stainless steel for longer life and measure 15" long with 3-1/2" diameter outlets. Two inlet sizes are available to fit 2-1/4" and 2-1/2" outer diameter exhaust pipes. Exhaust Tips can be welded on or clamped on with #31-0560 or #31-0561 Stainless Steel Exhaust Clamps that must be purchased separately.