The product is a set of service and parts manuals for the Detroit Diesel Inline 71 Series engine, specifically designed for model year 1984 (parts manual was printed in 1981). These manuals are essential for maintaining and repairing this diesel engine, providing detailed information on how to properly service and troubleshoot the vehicle. With a focus on diesel engines and compatibility with Detroit Diesel equipment, these manuals are a valuable resource for those looking to keep their heavy equipment in top condition. Made in the United States, this set of manuals is a must-have for anyone working with this specific engine model.