BS EN 12209 classifies mechanically operated locks, latches and locking plates using an 11 digit coding system. This has proved necessary in order to provide a proper assessment of all the varied features of products for specific markets within Europe. It should be noted that to avoid a greater proliferation of boxes, certain features have been “doubled up”: e.g. durability and durability with side load; door mass and closing force; corrosion resistance and temperature resistance. The system is comprehensive but it has led to the use of letters (rather than numbers) in certain boxes, since there can only be one digit in each classification box. A similar classification system applies to all building hardware product standards (at least for the first 7 boxes) to aid meaningful comparisons with related products.