Interstate Transportation of Obscene Material (for Purposes of Sale or Distribution) is the illegal transportation of obscene materials across state lines for the purpose of selling or distributing them. This includes the shipment of obscene books, magazines, photographs, films, and other media materials. It is a federal felony under Title 18 of the United States Code. There are three main types of interstate transportation of obscene material: physical transportation, electronic transmission, and mailing. In physical transportation, obscene materials are transported in physical form, such as in a truck, train, or plane. Electronic transmission is the transmission of obscene materials over the internet, such as through email, websites, and file sharing networks. Mailing is the sending of obscene materials through the United States Postal Service.