  Extreme TeV BL Lacs are a class of blazars with unique spectral and temporal
features, not easily reproducible using standard one-zone models based on
single shock acceleration. To account for their peculiar properties we
elaborated a two-steps acceleration model where a recollimation shock and the
subsequent downstream turbulence energize non-thermal electrons. We apply the
model to a sample of Extreme TeV BL Lacs with well characterized spectral
energy distributions. Since we are considering several sources, we automatized
the exploration of the parameter space. This also allows us to derive the
parameter distributions and to study the correlations among them. We
numerically solved a system of two coupled non-linear differential equations to
obtain the non-thermal particles and turbulence spectra. We calculated the
spectral energy distribution via the Synchrotron Self-Compton emission model.
The automatization of the parameter space exploration is possible through a
Markov Chain Monte Carlo (MCMC) ensemble sampler, in our case emcee. We derived
well defined posterior distributions for the parameters, showing that the model
is well constrained by available data and supporting the suitability of our
method. The cross-correlations among some of the physical parameters are not
trivial, therefore we conclude that MCMC sampling is a key instrument to
characterize the complexity of our multi-parametric phenomenological model.
