What is the difference in 420D and 600D fabric?

The difference between 420D and 600D fabric primarily lies in their denier measurement, which indicates the thickness of the fibers used. 600D fabric is thicker and generally more durable than 420D, making it better suited for heavy-duty applications such as backpacks and outdoor gear. In contrast, 420D fabric is lighter and more flexible, often used for lighter bags and accessories where weight savings are important. Overall, the choice between the two depends on the intended use and required durability.