Many of the toilet and sink manufacturers have a similar glaze. On some it's optional, on others, it's standard, but may not be offered on all choices or colors. On Totos, it's standard on some, optional on others. Having had toilets both with and without this type of glaze, those with it are much easier to clean - if it doesn't wash off on its own, it brushes off, generally with no extraordinary scrubbing. Easily worth the extra. And, if you don't use abrasives or caustic chemicals, should last the life of the toilet.