  The advent of Fermi is changing our understanding on the radio and gamma-ray
emission in Active Galactic Nuclei. In fact, contrary to previous campaigns,
Fermi mission reveals that BL Lac objects are the most abundant emitters in
gamma-ray band. However, since they are relatively weak sources, most of their
parsec scale structure as their multifrequency properties are poorly understood
and/or not systematically investigated. Our main goal is to analyse, using a
multiwavelength approach, the nuclear properties of an homogeneous sample of 42
faint BL Lacs, selected, for the first time in literature, with no constraint
on their radio and gamma-ray flux densities/emission. We began asking and
obtaining new VLBA observations at 8 and 15 GHz for the whole sample. We
derived fundamental parameters as radio flux densities, spectral index
information, and parsec scale structure. Moreover, we investigated their
gamma-ray emission properties using the 2LAT Fermi results. Here, we report our
preliminary results on the radio and gamma-ray properties of this sample of
faint BL Lacs. In the next future, we will complete the multiwavelength
analysis.
