  The Abbott-Deser mass, the Hamiltonian and the Komar mass of the
5-dimensional Kaluza-Klein black hole with squashed horizons take different
values. Introducing a new couple of thermodynamic variables for the Komar mass,
we show that each mass can be interpreted as a thermodynamic potential with its
own natural variables, i.e. all masses are related to each other by the
Legendre transformations. It is found that the new variables and the
gravitational tension represent the squashing of the outer horizon.
