 In some quarters, the fact that the most traditional models of quantum logics lack a reasonable tensor product have have been seen as heralding the collapse of the entire quantum-logical enterprise. This reaction is premature. The Foulis-Randall example, for instance, shows that there can be no general tensor product that behaves properly on all orthomodular lattices or orthomodular posets (that is, orthocoherent orthoalgebras), and on all states thereon. But this does not rule out the existence of a satisfactory tensor product for classes of structures larger than that of orthomodular posets, or smaller than that of orthomodular lattices, or for classes of orthomodular lattices or posets with restricted state spaces. Quantum Mechanics itself provides one example.  For another, as Foulis and Randall showed in Foulis and Randall [1981a], the class of unital orthoalgebras—that is, orthoalgebras in which every proposition has probability 1 in some state—does support a canonical tensor product satisfying their conditions (a) and (b).  