Amazon offers over 20 different ID card holders from DURABLE"s factories in Germany and Poland. All can be used with horizontal or vertical ID cards and are available in versions to accommodate one or two cards. The DURABLE two-card holders prevent the cards from touching each other which is a potential cause of data corruption in the magnetic stripe. DURABLE offers 2 styles of ID card holders - Open Face and Shell Style. The open face units are made of specially formulated Polystyrene and the shell style units which completely enclose the ID card are made of Acryl. Both materials have been formulated to withstand even the extreme climate of the Arctic. For Single Cards - Open Face Style, see DBL811819, DBL801119, DBL826619 and DBL891819. For Single Cards - Shell Style, see DBL800519, DBL801219, DBL826819 and DBL890519. For Two Cards - Open Face Style, see DBL821819, DBL821919, DBL826719 and DBL891919. For Two Cards - Shell Style, see DBL801319, DBL822419, DBL826919 and DBL822419.