I carry a couple of these as a spare E string to go with the EPS600 set (013-017-026w-036-046-056). In that context, and the fact that it comes in a sealed bag to prevent corrosion, these are just about perfect.
For those who use heavier gauge strings, unlike some other manufacture's strings, D'Addario's don't seem to suffer from the same kind of tightening (like to noose) around the ball-end when you tune up to concert. (i.e. D'Addario are not assuming that the 013 is a lower tension B string.)
If you're looking for a spare string for a D'Addario set, you know exactly what this sound like. Recommended.