  Recent X-ray surveys have provided a large number of high-luminosity,
obscured Active Galactic Nuclei (AGN), the so-called Type 2 quasars. Despite
the large amount of multi-wavelength supporting data, the main parameters
related to the black holes harbored in such AGN are still poorly known. Here we
present the results obtained for a sample of eight Type 2 quasars in the
redshift range 0.9-2.1 selected from the HELLAS2XMM survey, for which we used
Ks-band, Spitzer IRAC and MIPS data at 24 micron to estimate bolometric
corrections, black hole masses, and Eddington ratios.
