The Peterbilt 357, 359, 377, 378, and 379 Stainless Steel Lower Coolant Tube is a durable and practical solution for your truck's cooling system. Made from 304 stainless steel, this tube is built to last. It fits most Peterbilt 357, 359, 377, 378, and 379 models with ACERT engines, providing a reliable and efficient cooling solution. With OEM and aftermarket numbers F66-6251 and 666251, this tube is a perfect replacement for your truck's lower coolant tube. Invest in this high-quality product to ensure optimal performance and longevity for your truck's cooling system.