The Kenworth W900L 6 Inch Elbow Right Side is a practical and reliable product that fits most Kenworth 2003 and 2006 Aerocab W900L models. With a 6 Inch to 5 Inch size and a 40 step, this elbow is designed to accept a 6 Inch O.D. stack. It also features a Taper-Loc Reduction on the top side of the elbow, making it easy to install. Sold individually, this Kenworth W900L 6 Inch Elbow is a great choice for those looking for a high-quality and durable product that will last for years to come. Don't forget to check the OEM number - M66-1270CP - before purchasing.