The Curved Stack 4 Inch I.D Aluminized - 18 Inches is a practical and versatile product that fits most makes and models. With its curved design, 4 inch ID, and aluminized construction, this stack offers durability and efficient performance. Measuring 18 inches in length, it is suitable for various applications. Sold individually, this stack is a reliable choice for those seeking a high-quality and functional solution.