You close this bag with a zipper. The choice of material is polyester.
From SmartTeck
Rivacase Tegel 8460 backpack Black Polyester -
ShopBetter24
Laptop Case Rivacase Tegel ECO Black 17,3"
Shopaide
Laptop Case Rivacase Tegel ECO Black 17,3"
OnBuy
RIVACASE 8460 17 Inch Laptop Backpack with Luggage Strap,Travel Bag Rucksack College Student Shoulder Back Pack For Up to 17 Inches Laptop Notebook