DGR 18.104.22.168.1 stipulates that the letters UN or ID and the numbers must be at least 12mm high. For packages of a capacity less than 30L or 30kg and for cylinders with a water capacity of 60L, the height of the letters/numerals must be 6mm high. For packages less than 5L or 5kg, the size must be of an appropriate size. As for the size of all other markings. i.e., Proper Shipping Name, names and addresses of the Shipper and of the Consignee, etc.) DGR 22.214.171.124.2 stipulates that the size must be at least 12mm high, and for packages of 30L or 30kg capacity, 6mm high.