The reason that our Webber Gage Division emphasizes gage blocks made from Chromium Carbide is because they are the most stable measuring devices ever developed.
Chromium Carbide gage blocks are considered the top of the line; the finest available. They outwear regular steel and ceramic. In addition, they will not corrode, are very stable and accurate, and have exceptional "wringing" qualities.
No one in the world except Starrett-Webber has produced the accuracy and stability of our croblox Grand Masters. They were produced in 1955 of Chromium Carbide material to an accuracy within one millionth of an inch (.0000254mm) and have been checked periodically by the U.S. National Bureau of Standards and the U.S. National Institute of Standards and Technology (NIST) and have remained stable over this period.