  We study the thermodynamics of the KS black hole which is an asymptotically
flat solution of the HL gravity. In particular, we introduce a cavity to
describe the thermodynamics at a finite isothermal surface on general ground
and to get a well-defined thermodynamics. We show that there exists a locally
stable small black hole which tunnels to the hot flat space below the critical
temperature and to the large black hole above the critical temperature.
Moreover, it turns out that the remnant decays into the vacuum through a
quantum tunneling.
