We are frequently asked to quote on gage blocks made to non-standard dimensions. Requests like this leads to a number of questions, the first question being why they are needed in the first place.
The answer would seem obvious: a very accurate master is required to set up a comparative measuring device that will be used in a production setting. Since gage blocks are the most popular representation of highly precise dimensional masters, they become the default request. But there is more to it all.