Quiet-Flow™ Stainless Steel Oval Aluminized Exhaust Muffler (21563) by Walker®. Direct OE Replacement. Together with delivering OE-style sound, the Quiet-Flow Muffler features 100% structural stainless steel construction that resists rust three times longer than aluminized mufflers offered by competitors. This part is a perfect decision if you are looking for proper OE-quality acoustics and long service life.