Is 420 denier nylon the same as 4 oz?

No, 420 denier nylon and 4 oz are not the same; they refer to different measurements. Denier (den) measures the thickness of the fibers in the fabric, while ounces (oz) typically refer to the weight of the fabric per square yard. A 420 denier nylon fabric is relatively durable and strong, while 4 oz indicates a lighter weight fabric. The two measurements provide different information about the material's properties.