Comparison of the fiber properties in NGC 1333 (red solid histograms; upper panel) and B213-L1495 (blue solid histograms, lower panel; Hacar et al. 2013). The main properties of the subgroup of fertile fibers found in B213-L1495 are highlighted in red in the lower panel. From left to right: a) total fiber length; b) internal non-thermal motions (in units of the sound speed c_s); and c) mass-per-unit-length.