We study the doubly charged Callan-Giddings-Harvey-Strominger model, which has black hole solutions that were found to be U dual to the DI-DS-KK black holes of type IIB supergravity. We derive the action of the model via a spontaneous compactification on S-3 Of type IIB supergravity on S-1 X T-4 and obtain the general static solutions including black holes corresponding to certain nonasymptotically flat black holes in type IIB supergravity. The thermodynamics of them is established by computing the entropy, temperature, chemical potentials, and mass in the two-dimensional setup, and the first law of thermodynamics is explicitly verified. The entropy is in precise agreement with that of the D1-D5-KK black holes, and the mass turns out to be consistent with the infinite Lorentz boost along the M theory circle that is a part of the aforementioned U-dual chain. [S0556-2821(98)00422-6].