  The Supersymmetric Custodial Triplet Model, a supersymmetric generalization
of the Georgi-Machacek model, has proven to be an interesting modification of
the MSSM. It extends the MSSM Higgs sector by three extra SU(2)L triplets in
such a way that approximate custodial invariance is preserved and rho-parameter
deviations are kept under control. By means of a sizeable triplet contribution
to electroweak breaking the model is able to generate a barrier at tree level
between the false vacuum and the electroweak one. This will result in a strong
first order phase transition for an important region of the parameter space. We
also look at the gravitational waves that could be generated as a result of the
phase transition and show how future interferometers could be used as a probe
of the model.
