BeppoSAX ToO Observations on BLAZARS

We summarize the results of BeppoSAX ToO observation of blazars that were known to be in a high state from observations carried out in the optical or X-ray or TeV bands. In some of the sources observed, two spectral components were detected, which are interpreted as synchrotron and inverse Compton emission, respectively. Fast variability was detected in three sources (ON231, BLLac and S5 0716+714), but always only for the synchrotron component. Most of the triggers are from optical observations, consequently most of the sources observed are LBL or intermediate objects. They were in a high state in the X-ray band, but not in an exceptionally high state. No strong shift in the synchrotron peak frequency are reported. This is in line with the findings that the synchrotron peak frequency is more variable for HBL objects, i.e. sources that have this peak at higher energies.