CoolBELL Water Resistant Nylon Unisex Slim 17.3 inch Laptop Messenger Bag Briefcase Handbag (Grey) PREMIUM MATERIAL: This stylish slim briefcase is made of water resistant Nylon material. For the inner lining, soft feel polyester fabric is used. The metal fittings such as zipper heads and strengthened metal hooks used are smooth, sturdy and durable.