  We consider an alternative approach to a fundamental CR invariant - the
Catlin multitype. It is applied to a general smooth hypersurface in
$\mathbbC^{n+1}$, not necessarily pseudoconvex. Using this approach, we prove
biholomorphic equivalence of models, and give an explicit description of
biholomorphisms between different models. A constructive finite algorithm for
computing the multitype is described. The results can be viewed a necessary
step in understanding local biholomorphic equivalence of Levi degenerate
hypersurfaces of finite Catlin multitype.
