Unknown drawing callout 1

This is ISO 13715 - Technical product documentation — Edges of undefined shape —Indication and dimensioning

minus dimension means a chamfer/radius, positive means allowable burr size.

This system is mostly used by German engineering corps but it's not widespread and one contributing factor is in my opinion is the lack of support from CAD applications. I've yet to see a CAD software which contains the symbology for this standard. We used to sketch our own symbols and write macros, logics to apply and in the end we gave up on the whole ISO 13715 system

An interesting question: is the edge a feature and the answer is different in ASME versus ISO GPS?
And, but I might be wrong here, I don't think ISO13715 is a GPS standard, is it?

Let me know what do you think?

Greenimi -- GPS is an umbrella of many standards (we usually think of GD&T, but it also includes surface finish, edge/corner breaks, etc.).
But ASME doesn't use this edge/corner stuff in its realm.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

It falls under ISO/TC 10 "Technical product documentation"

ISO GPS falls under ISO/TC 213 "Dimensional and geometrical product specifications and verification"

Thank you all for the informative replies, the fact this callout is ISO codified while at the same time being out of GPS&V is interesting (and somewhat confusing).

TC stands for Technical Committee. These are organization subgroups under the whole ISO organization umbrella.
ISO TC10 and TC213 are committees which can access each others work and connect them.

If you have a cookbook from two different authors but with a same receipt you can create a very delicious meal. Weird example I know.