- USB charge support - Concealed strap design - Soft handle - Air cussion belt CoolBell CB-504 is a multifunction waterproof laptop backpack bag with built-in USB 2.0 port for charging phones conveniently when power bank is connected. It is designed with fine fabric materials, padded and water resistant knapsack. Additionally, an anti-theft pocket is added to the back of the bag for safe keeping of precious items thereby protecting your personal belongings. The bag fit up to 15.6 inches laptops and it has enough room for keeping laptop accessories like Power-Cord, Mouse, Pens, Books, Documents, iPad, etc. The Belt of the bag is designed in such a way that it allows fixing the bag to a luggage trolley. It can convert to backpack and briefcase (i.e. side/shoulder bag) as you want. Brand coolbell SKU 100278028_NP-1020539514 Model 504