Most recent
DIN 863-4:1999
Micrometers - Internal micrometers - Concepts, requirements and testing
The document applies to internal micrometers for dimensions up to 500 mm, with a maximal measuring range of 25 mm and a scale interval and a resolution of 0,01 mm respectively. It specifies the most important dimensional, functional and quality characteristics of internal micrometers and their testing.
Deutsches Institut für Normung [din]