The product is a technical manual in PDF format for John Deere 6620, 7720, and 8820 combines. It includes information on maintenance, operation, and troubleshooting for these specific models. This manual is a valuable resource for owners and operators of John Deere heavy equipment, providing detailed instructions and guidance on how to properly use and maintain the machines. It is compatible with John Deere equipment and is a must-have for anyone looking to maximize the performance and lifespan of their machinery.