  We define a family of spacetimes representing isolated black holes exhibiting
remarkable universal properties which are natural generalizations from
stationary spacetimes. They admit a well defined notion of surface gravity k_H.
This generalized surface gravity mediates an exponential relation between a
regular null coordinate w near the horizon and an asymptotic Bondi null
coordinate u defined in the vicinity of future null infinity. Our construction
provides a framework for the study of gravitational collapse of an isolated
system in its late stage of evolution.
