  Using a $U$-duality symmetry of type II compactification on $T^4$ represented
by triality action on the $T$-duality group, and applying the adiabatic
argument we construct dual pairs of type II compactifications in lower
dimensions. The simplicity of this construction makes it an ideal set up for
testing various conjectures about string dualities. In some of these models the
type II string has a perturbative non-abelian gauge symmetry. Examples include
models with $N=2,4,6$ supersymmetry in four dimensions. There are also
self-dual (in the sense of $S-T$ exchange symmetric) $N=2$ and $N=6$ examples.
A generalization of the adiabatic argument can be used to construct dual pairs
of models with $N=1$ supersymmetry.
