Area (or entropy) products for Newman-Unti-Tamburino class of black holes

We compute area (or entropy) product formula for Newman-Unti-Tamburino (NUT) class of black holes. Specifically, we derive the area product of outer horizon and inner horizon (H^±) for Taub-NUT, Euclidean Taub-NUT black hole, Reissner-Nordström-Taub-NUT black hole, Kerr-Taub-NUT black hole and Kerr-Newman-Taub-NUT black hole under the formalism developed very recently by Wu et al. (2019) [1]. The formalism is that a generic four dimensional Taub-NUT spacetime should be described completely in terms of three or four different types of thermodynamic hairs. They are defined as the Komar mass (M = m), the angular momentum (J_n = m n), the gravitomagnetic charge (N = n), the dual (magnetic) mass (M ∼ = n). After incorporating this formalism, we show that the area (or entropy) product of both the horizons for NUT class of black holes are mass-independent. Consequently, the area product of H^± for these black holes are universal. Which was previously known in the literature that the area product of said black holes are mass-dependent. Finally, we can say that this universality is solely due to the presence of new conserved chargesJ_N = M N which is closely analogue to the Kerr like angular momentum J = a M.