Strength Indicators D (denier)
D (denier) - Denier is a metric used to describe what is essentially thickness or density. It was originally intended to measure varying sizes of strands of silk and is the mass in grams of 9,000 meters of the yarn, so it’s not technically correct to call it density, which is mass per unit volume.
When you see a backpack that is 450D nylon or 900D polyester, that means that 9,000 meters of that fabric weighs 450 grams and 900 grams respectively.
The higher the denier, the stronger the fabric (in general, but only intra-material). This does not translate directly across different fabrics, as each fabric is also inherently different in strength. For example 450D nylon is actually stronger than 600D polyester.
Adventure backpacks used for hiking and camping can commonly be found in the range of 450-600D nylon.