On non-tachyonic ZN×ZM orientifolds of type 0B string theory

We study open descendants of four dimensional ZN×ZM orbifolds of the non-supersymmetric type 0B string theory. An exhaustive analysis shows that using the crosscap constraint the only model for which one can project out the tachyon is the Z2×Z2 orbifold. For this case we explicitly construct the open string amplitudes. The gauge group corresponding to the various inequivalent Klein bottle projections turns out to be either symplectic or unitary.