An apparatus arranged to heat but not burn smokable material to volatilise at least one component of the smokable material, the apparatus comprising: a housing having an insertion point formed in a collar at one end, through which a consumable article comprising smokable material can be removably inserted into the apparatus in use; at least one heater arrangement arranged within the housing for heating said smokable material within the consumable article when in use; and a chamber comprising a tubular body, the chamber located in the housing between the collar and the at least one heater arrangement; wherein, when the consumable article is inserted into the apparatus, the housing comprises ventilation around the outside of said consumable article at the insertion point to enable at least one heated volatilised component from said smokable material to exit the apparatus and/or air to enter the apparatus; wherein the collar comprises a plurality of ridges arranged circumferentially around the insertion point that project into the insertion point; wherein a first ventilation path is defined between a first neighbouring pair of the plurality of ridges and wherein the ventilation is provided by the first ventilation path; wherein a second ventilation path is defined between a second neighbouring pair of the plurality of ridges and wherein the ventilation is additionally provided by the second ventilation path; wherein the plurality of ridges protrude into the insertion point to reduce the span of the insertion point at the location of the plurality of ridges; wherein the collar is distinct from the housing and an open end of the chamber connects to and is supported by the collar; wherein the chamber comprises a plurality of small lobes or ridges arranged circumferentially around an inner surface of the chamber; and wherein apparatus further comprises a heater chamber arranged co-axially with the chamber and the collar such that, when the consumable article is inserted in the apparatus, it extends through the collar and the chamber into the heater chamber; and wherein the apparatus further comprises: control circuitry configured and arranged to control the heating of the smokable material in the consumable article; and a power source comprising a battery, wherein the battery is electrically coupled to the heater arrangement to supply electrical power when required and under control of the control circuitry to heat the smokable material in the consumable article to volatise the smokable material without causing the smokable material to burn. a housing having an insertion point formed in a collar at one end, through which a consumable article comprising smokable material can be removably inserted into the apparatus in use; at least one heater arrangement arranged within the housing for heating said smokable material within the consumable article when in use; and a chamber comprising a tubular body, the chamber located in the housing between the collar and the at least one heater arrangement; wherein, when the consumable article is inserted into the apparatus, the housing comprises ventilation around the outside of said consumable article at the insertion point to enable at least one heated volatilised component from said smokable material to exit the apparatus and/or air to enter the apparatus; wherein the collar comprises a plurality of ridges arranged circumferentially around the insertion point that project into the insertion point; wherein a first ventilation path is defined between a first neighbouring pair of the plurality of ridges and wherein the ventilation is provided by the first ventilation path; wherein a second ventilation path is defined between a second neighbouring pair of the plurality of ridges and wherein the ventilation is additionally provided by the second ventilation path; wherein the plurality of ridges protrude into the insertion point to reduce the span of the insertion point at the location of the plurality of ridges; wherein the collar is distinct from the housing and an open end of the chamber connects to and is supported by the collar; wherein the chamber comprises a plurality of small lobes or ridges arranged circumferentially around an inner surface of the chamber; and wherein apparatus further comprises a heater chamber arranged co-axially with the chamber and the collar such that, when the consumable article is inserted in the apparatus, it extends through the collar and the chamber into the heater chamber; and wherein the apparatus further comprises: control circuitry configured and arranged to control the heating of the smokable material in the consumable article; and a power source comprising a battery, wherein the battery is electrically coupled to the heater arrangement to supply electrical power when required and under control of the control circuitry to heat the smokable material in the consumable article to volatise the smokable material without causing the smokable material to burn. control circuitry configured and arranged to control the heating of the smokable material in the consumable article; and a power source comprising a battery, wherein the battery is electrically coupled to the heater arrangement to supply electrical power when required and under control of the control circuitry to heat the smokable material in the consumable article to volatise the smokable material without causing the smokable material to burn.