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For $r_{-}<r_{+}$, an ingoing chart with $v=t+r_{\ast }$ has metric $-Vd{v}^2+2dvdr+R^{2}d{\Omega }_2^2$. In its future interior, $\nabla r={\partial }_v+V{\partial }_r$ is future timelike, so every future causal curve decreases $r$ and cannot reach future null infinity. The singularity $r=r_{-}$ is spacelike. A Kruskal–Szekeres coordinates extension has the same qualitative Penrose diagram as Schwarzschild spacetime, with two exterior regions, a future black-hole interior and a past white hole interior. The past interior has the same radial interval but is not a black hole region; specifying the radial interval alone does not identify the future component. For $r_{-}>r_{+}$, the physical exterior $r>r_{-}$ has $V>0$ everywhere and outgoing null rays escape from arbitrarily near a timelike naked singularity.

The static spherically symmetric electrically charged black hole in five spacetime dimensions has $f(r)=1-2M/r^2+Q^2/r^4$. When $M>Q$ it has outer and inner horizon radii $r_{\pm }^2=M\pm \sqrt{M^2-Q^2}$; for $M=Q$ it is an extremal black hole, while $M<Q$ exposes a naked singularity.

The zeros of $f$ give three causal structures.

Thus the cases are subextremal, extremal, and overextremal according as $M>Q$, $M=Q$, and $M<Q$.