This Outside Micrometer comes with Extension Anvil Collars. 

It offers you the following benefits: 

• The collars have a stable and rugged yet lightweight tube construction, and are ideal for large micrometers. 
• The 50mm spindle stroke gives you extended range compared to standard spindle types. 
• Anvil collars extend the measuring range even further. 
• The setting standards supplied cover the whole measuring range.