  In this paper we present a new way to construct the pro-category of a
category. This new model is very convenient to work with in certain situations.
We present a few applications of this new model, the most important of which
solves an open problem of Isaksen [Isa] concerning the existence of functorial
factorizations in what is known as the strict model structure on a
pro-category. Additionally we explain and correct an error in one of the
standard references on pro-categories.
