A gauge block (also known as a gage block, Johansson gauge, slip gauge, or Jo block) is a precision ground and lapped length measuring standard. It is used as a reference for the setting of measuring equipment used in machine shops, such as micrometers, sine bars, digital calipers, and dial indicators (when used in an inspection role)

 

Three leves: 0, 1, 2.

Including: 10, 20, 20, 41.2,81.5, 121.8