Location of the cusp (r_in) and the outer radius (r_out) of the cusp tori for different values of r₀ and space-time parameters, increasing in q/j² from left to right. The curves denoting inner and outer radii merge in the limit of the slender cusp torus, i.e. when r₀ = r_ISCO. The behaviour for the non-rotating case corresponds to the situation depicted along with several related details in the middle panel of Fig. 1.