According to some embodiments there is provided a device configured for releasing at least one substance from source material, comprising: a housing； a plurality of source material sections positioned at fixed locations with respect to the housing； a plurality of airflow paths, each airflow path associated with at least one source material section； each airflow path associated with at least one blocking element which prevents flow of air through the path； and an actuator operably coupled to the blocking element, the actuator configured for unblocking the airflow path of at least one selected source material section to allow flow of air to and through source material within the selected section.
