  In earlier work, we derived formal matched asymptotic profiles for families
of Ricci flow solutions developing Type-II degenerate neckpinches. In the
present work, we prove that there do exist Ricci flow solutions that develop
singularities modeled on each such profile. In particular, we show that for
each positive integer $k\geq3$, there exist compact solutions in all dimensions
$m\geq3$ that become singular at the rate (T-t)^{-2+2/k}$.
