  We prove that if $X|_\Lambda$ has the weak specification property robustly,
where $\Lambda$ is an isolated set, then $\Lambda$ is a hyperbolic
topologically mixing set and, as a consequence, if $X$ is a vector field that
has the weak specification property robustly on a closed manifold $M$, then the
flow $X_t$ is a topologically mixing Anosov flow. Also we prove that there
exists a residual subset $\SR \in \Mundo$ so that if $X \in \SR$ and $X$ has
the weak specification property, then $X_t$ is an Anosov flow.
