A heavy-duty shrink tunnel is used in file manufacturing for securely packaging finished box files and folders by shrinking plastic film tightly around the products using controlled heat. This process ensures neat, tamper-proof, and moisture-resistant packaging that protects files from dust, damage, and handling during storage and transportation. The shrink tunnel enhances product presentation, maintains bundle integrity, and increases packing speed while reducing manual effort. It also helps improve durability, reduces transit losses, and delivers a professional, market-ready finish to the final product.