  Using the QCD sum rules technique we study several aspects of the
phenomenology of the b-flavoured strange meson $B_s^0$. In particular, we
evaluate the mass of the particle, the leptonic constant and the form factors
of the decays $\overline {B_s^0} \to D^{+}_s \ell^- \bar\nu$, $\overline
{B_s^0} \to D^{*+}_s \ell^- \bar\nu$, $\overline {B_s^0} \to K^{*+} \ell^-
\bar\nu$. We also calculate, in the factorization approximation, a number of
two-body non leptonic $\overline {B_s^0}$ decays.
