Material:Made of high quality kraft paper, thick and durable. It is anti-slip and not easy to be ripped, can be reused several times. Special Design:Very durable string envelope，come with a top opening for easy retrieval of documents,String closure to prevent the paper from falling off, keeps your important documents safe and secure. Usage:Ideal for store all kinds of documents, bills, datas and other school and office supplies for Business, Office, School, Test field, business travel.