Product Features:The lightweight backpacks are made of polyester. Polyester material is heat resistant, making it suitable for outdoor use. 1.Ergonomic, dual padded, reinforced, adjustable shoulder straps. This provides optimum comfort for your shoulders. Adjustable shoulder straps are perfect for choosing the appropriate length 2.Fully-padded back panels. Basic backpack delivers optimum comfort for your back with the full padding feature.3.Good quality brand zipper featuring extra long zipper puller. zippers are solid and sturdy. It doesnt easily break off even with constant use. Plus, it feels secure and holds nicely.4.The outer shell of the backpack is made of waterproof fabric so there is no worry that the backpack would get wet in drizzle.5.Rain cover is located at the boom of the backpack,and directly pull it out to cover the backpack in the heavy rain.Shockproof Airbag:The shockproof laptop sleeve is full side padded with a velcro closure,which could secure your laptop from scratches and bumps.How to use the external USB function? Step1: Attach your mobile phone on the suction cup phone holder located on the left shoulder strap; Step2: Connect it to the external USB port, the other end of which connects to a removable charging cable built inside of the main compartment; Step3: Connect the charging cable with a power bank.ackage including: 1x backpack Note: The load this backpack bears had better not be over 10KG.