Still some questions about fabrics used for bags : ManyBaggers
The Timbuk2 CMB is an 1830D polyester constructed using a plain weave ("plain weave", weirdly enough, means something very specific in fabric engineering circles.) Cordura is, like YKK, a brand name with a long history and good durability, but in and of itself a bag being made of "Cordura" tells you nothing about the materials, denier, etc.