  We examine the fission barriers, mass parameters and spontaneous fission half
lives of fermium isotopes within the framework of macroscopic-microscopic model
with a $\delta$-pairing interaction. Four different macroscopic models are
applied and studied. The results are compared to experimental data and to the
corresponding monopole pairing ones. The half lives obtained in the
$\delta$-pairing model are comparable with experimental data. The
state-dependence of pairing has an important effect on the calculated fission
half-lives.
