  We present the results of two ToO BeppoSAX observations of BL Lac. During the
first observation we detected both the synchrotron and the Compton components.
Fast time variability was present, but only for the synchrotron component.
During the second observation the spectrum was flatter and only the Compton
component was present. Four different SED are presented and can be described by
a blob moving along a jet and responsible for the SSC emission. The seed
photons for the Compton scattering are the synchrotron photons themself plus
possibly external photons coming from the broad line region.
