CAII might be thinner in order to minimize jamming in certain automated transport gear, but it's also a distinctly whiter base than the previous Super C with cleaner color, so this probably also has something to do with the specific choice. Damn good paper; but you do need to be a little more careful handling large sheets of it. They do also offer a premium thicker paper in certain markets, but perhaps in more limited sizes. I cut my teeth on polyester papers, which won't tolerate any handling mistakes at all, so working with the new thinner paper doesn't pose any problems for me personally. Cut sizes are avail only up to 20X24; anything bigger is now rolls only.