Nylon 645 is a transparent nylon filament that is suitable for industrial manufacturing. Its transparent nature makes it easy to inspect for defects and print quality. Its high strength and relative rigidity compared to other nylons makes it ideal for high stress industrial applications where flexible, nylon-like behavior is desired. Nylon 645 also has a slippery surface that eliminates the need for lubricants on the part. For those who need a flexible material that will hold up to heavy loads, Nylon 645 is a good choice.