Symbol on Draft (Tolerance?)

[henrybroeker]

Dear colleagues,

I stumbled over one symbol which I am not sure what it means:

What is the half-circle with the 0.5? Is this the tolerance?

Thanks for your help,

Henry

 

[pmarc]

This is profile of a surface tolerance symbol.

There are many free web sources where you can find more info about what it exactly is and how it works.