Abstract: Evaporator-block container having an adjustable cross section of the outlet aperture and comprising two housing components of which the one is a retaining part suitable for holding an evaporator block, the said retaining part having at least one outlet aperture for the outlet of vapors of an active substance contained in the evaporator block, and the other is a sealing part which seals or closes in an adjustable manner, either completely or partially, the outlet aperture(s) and which is connected with the retaining part in the closed position to give a sealed but releasable closure, characterized in that there is incorporated inside the housing parts a mould having an inlet aperture facing the sealing part, which is for the pouring in of evaoporator-block material in the melted state.