Using a zipper to close a bag is as easy as it gets. Since it only comes in black, your colour choice is made very easy.
From OnBuy
HP 1X644AA N1 Prelude - Notebook carrying backpack - 15.6" - for 25X G8; 1X644AA
Technoworld PLC
HP Prelude Pro 15.6-inch Recycled Backpack
This product is also available at 4 unverified stores.