  We present explicit results for the product of all horizon areas for general
rotating multi-charge black holes, both in asymptotically flat and
asymptotically anti-de Sitter spacetimes in four and higher dimensions. The
expressions are universal, and depend only on the quantized charges, quantized
angular momenta and the cosmological constant. If the latter is also quantized
these universal results may provide a "looking glass" for probing the
microscopics of general black holes.
