  In this paper we consider a magnetic analog of the double-Reissner-Nordstrom
solution and construct the corresponding magnetic potential A_\varphi in the
explicit form. The behavior of the resulting solution under the Harrison
transformation then naturally singles out the asymmetric black diholes -
configurations composed of two non-extreme black holes possessing unequal
masses, and charges equal in magnitude but opposite in sign - as its most
general subclass for which equilibrium of the black-hole constituents can be
achieved with the aid of the external magnetic (or electric) field. We also
generalize the double-Reissner-Nordstrom solution to the dilaton gravity with
arbitrary dilaton coupling, yielding as the result the 4-dimensional
double-Gibbons-Maeda spacetime. The study of some physical properties of the
solutions obtained leads, in particular, to very simple formulas for the areas
of the horizons and surface gravities.
