Similar password envelope，after printing the data, Can mail or self-use. To ensure the private data and the confidential document to deliver or mail safely，The addressee must open this product along the three knives' position，then can review the datas in it. There are various shadings to choose in order to ensure the printed contents' safety, and even raised the printing's security. glued well, easy to check. if opened, It is unable to recover. safe and secret. Whatever paper, thick or thin, all have various kinds to choose. they are mainly used in finance, social security bureau or enterprise's pay bill and figure guarantee ceter etc.