What is the material of the backpack?

Cloth - all nylon. Strong strength. All fabrics pass waterproof and decolorization tests to be used and can withstand up to 6000 runs. Hard and durable.
Zipper - all zippers have passed the honing test. According to statistics, the average daily zipper per schoolboy will be used about 25 times to calculate, to ensure that within three years the zipper will only wear and tear and will not damage
Reflective materials all use the internationally renowned brand 3M reflective materials. It can improve drivers' vigilance at night.
Back Sheath - ergonomically similar to the second spine, which distributes the weight of the schoolbag between the hips and pelvis.
Body design straps can scatter the weight of the schoolbag 80% to the hips and pelvis. Reduce back bone pressure.
Chest straps - stabilize schoolbags to reduce shoulder pressure and affect muscles.
Hip strap - Fix the bag on the hip to prevent the bag from swaying from side to side during walking and running. The weight can be averagely distributed in the spine, hip and pelvis.
The inner straps can locate the books in the schoolbag and do not swing left and right.
Webbing - Tensile test.