ISO ISO I say.....they want to put everything in cubes of that dimension. In fact the ISO museum in Pantelon, France is full of cubes each with a description of their composition and mass in kg. They even have a Borg cube but its mass is irrelevant. It tried to assimilate a litre of water but blew out all its light bulbs. Anyway I digress.....

.....a bit of basic mental arithmatic tells me that Hardox is heavier by 800g/m² for 4mm plate and 600g/m² for 3mm (any comments about being basic and mental will be ignored)