We are interested in GALFA-HI fibers. They tell us about the B-field. But how do they relate the microphysics? Two important unanswered questions are: do they have a characteristic width? There are arguments for a particular width, but GALFA-HI does not have the resolution to resolve them. And what is their dust content? Small grains control ISM heating, as they dominate the surface area, large grains control ISM metal content, as they dominate the grain volume. Both are important indicators of the content of the fibers. To check these we use Planck 353 emission data and WISE emission maps from \cite{Meisner_2013} and compare to the GALFA-HI DR2 data cubes