  We perform an analysis of two-body non leptonic decays of $B$ and $B_s$
mesons in the factorization approximation. We make use of the semileptonic
decay amplitudes previously calculated on the basis of an effective lagrangian
satisfying chiral and heavy quark symmetries and including spin 1 resonances.
Exclusive semileptonic $D$-decay data are used as experimental input. Our
results compare favorably with data, whenever they are available and indicate a
positive value for the ratio of non leptonic coefficients $a_2/a_1$, similarly
to previous studies.
