  The box product of Mackey functors has been studied extensively in Lewis's
notes. As shown in Thevenaz and Webb's paper, a Mackey functor may be
identified with a module over a certain algebra, called the Mackey algebra. We
aim at describing the box product, in the sense of Mackey algebra modules. For
a cyclic $p$-group $G$, we recover a result from Mazur's thesis. We generalize
it to a general finite group $G$ in this article.
