Mitutoyo 516-803-10 Wear Block sets grade 0 Nominal size 2mm, CarbideA pair of thin, wear resistant Mitutoyo gauge blocks designed to form the end (or ends) of a stack of blocks to absorb normal wear and tear. These are especially economic when the application involves abrasive contact with the end (or ends) of a stack, so that instead of wearing a large proportion of the blocks in a whole set, the wear is largely confined to a pair of relatively inexpensive, and therefore easily replaceable, gauge blocks.