2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/104564A system H with a Hagedorn-like mass spectrum imparts its unique temperature T_H to any other system coupled to it. An H system radiates particles in preexisting physical and chemical equilibrium. These particles form a saturated vapor at temperature T_H. This coexistence describes a first order phase transition. An H system is nearly indifferent to fragmentation into smaller H systems. A lower mass cut-off in the spectrum does not significantly alter the general picture. These properties of the Hagedorn thermostats naturally explain a single value of hadronization temperature observed in elementary particle collisions at high energies and lead to some experimental predictions.Contribution to the ``World Consensus Initiative III, Texas A & M University, College Station, Texas, USA, February 11-17, 2005, 15pHigh Energy Physics - Phenomenologytext