The larger one holds a pretty impressive amount of tea.
They recommend that you use it for fully oxidized teas, like my heaping helping of Darjeeling, because it is not completely air tight even with the two lids. I buy sencha in smaller quantities, so I got a few small screw lid tins for these.
I think it is a pretty cool looking piece, I bought it as much for decoration as for actually storing tea. It works pretty well for both.
Like your other tokoname pieces, it is expertly crafted. Everything fits together very well, and it is much lighter than you would expect.