  Non-supersymmetric black holes carrying both electric and magnetic charge
with respect to a single Kaluza-Klein gauge field have much in common with
supersymmetric black holes. Angular momentum conservation and other general
physics principles underlies some of their basic features. Kaluza-Klein black
holes are interpreted in string theory as bound states of D6-branes and
D0-branes. The microscopic theory reproduces the full nonlinear mass formula of
the extremal black holes.
