Using the approximate conformal invariance of QCD at high energies we consider a simple AdS black disk model to describe saturation in DIS. Deep inside saturation the structure functions have the same power law scaling, F(T) similar to F(L) similar to x(-omega), where. is related to the expansion rate of the black disk with energy. Furthermore, the ratio F(L)/F(T) is given by the universal value 1+omega/3+omega, independently of the target.