  In this paper, we describe the structure of the direct product of partial
Burnside rings of relative to the collection of a finite group. In particular,
we show that the unit group of the partial Burnside ring relative to the set of
all parabolic subgroups of a reducible finite Coxeter group is isomorphic to
the direct product of unit groups of the partial Burnside ring of irreducible
Coxeter group.
