  A consistent description of the confining QCD vacuum as a dual superconductor
requires a determination of fundamental parameters such as the superconductor
correlation length $\xi$ and the field penetration depth $\lambda$, which
determine whether the superconductor is of type I or type II. We illustrate
preliminary results of a lattice determination of $\xi$ for the case of pure
Yang-Mills with two colors, obtained by measuring the temporal correlator of a
disorder parameter detecting dual superconductivity.
