an alkali metal a hydrate of the inorganic salts of alkali a hydrated salt a eutectic of the chlorides a nitrate an acetate and an ammoniate of the light metals the heat absorbing material 104 may include only a single endothermic material or any combination of endothermic materials the heat absorbing material 104 may be microencapsulated referring now to fig2 there is illustrated an electronic device 200 mounted on a pcb 201 the electronic device 200 is thermally and physically connected to the pcb 201 by way of a first thermal structural bond 208 the pcb 201 is thermally and physically connected to a housing 203 by way of a second thermal structural bond 202 the housing 203 contains a first heat absorbing material 204 which is a means for a first heat transfer 205 and a second heat absorbing material 206 which is a means for a second heat transfer 209 from the electronic device 200 the housing 203 is a thermally conductive structure which contains a first heat absorbing material 204 and a second heat absorbing material 206 the first heat absorbing material 204 may be the same as the second heat absorbing material alternatively the first heat absorbing material 204 may.