Because the road bike bags used in special environments, materials and workmanship backpack made a higher demand. All positions backpack forces are using suture needle sewn back three times, so that by the power of the position durable. Backpack snaps can be done antifreeze and other components, as well as anti-smashing 120 degrees Celsius deformation is not damaged. Backpack outside material mainly 420D Oxford nylon, 1000D nylon, 600D or 1000Dpolyester (polyester), or 1000D CORDVRA other materials. 1000D high-density material, very wearable, very suitable for use in the field. DuPont developed CORDVRA is very prestigious and durable nylon roving fabric. The wear resistance of the material is much higher than normal nylon or polyester, and light weight. More than 90 percent of the world's famous brands of backpacks are using this prestigious nylon material. These materials can withstand 0.5m ~ 2m of water pressure, so that the bag body remains dry. Some material also tear function, once punctured, the break will not be torn to expand.