The 'round wound' strings work excellent for things like radiator hoses on autos and such, cables as well I would suppose.

The other strings make excellent antennas as they aren't wrapped (wound) and are 'springy' so they don't usually break.

The gauges are the diameter of the strings:

[ATTACH=full]6405[/ATTACH]

I just ordered them as well, although I'll probably be stringing my guitar with them and using the ones I take off for modeling purposes, that is either a huge typo or the best deal ever. One set at my LMS is at least $8.00 for one pack of D'Addarios