Apparatus for dosing volatile active ingredient

A dispensing device for dispensing a volatile active ingredient from an air-transmitting substrate that forms a part of a refill assembly. The dispensing device includes a housing which has a foot (78) with an angled support surface and a horizontal support surface. The housing has an intake vent and an exit vent and an air flow path extending between them. Refill assembly support means are provided for removably supporting the refill assembly with its substrate located in the air flow path. Battery-powered fan means are provided for propelling air from the intake vent through the substrate and out the exit vent. The battery is positioned in the device sufficiently far forward that the centre of gravity of the device is above the horizontal support surface of the foot when the device is resting on the foot, and is above the angled support surface when the device is nesting on the angled surface. This makes the device stable in both an horizontal position, or in a tilted position. An air-transmitting refill assembly for use with the dispensing device includes an air-transmitting substrate and a tab attached to the margin of the substrate. The tab has a brace surface facing generally away from the substrate and shaped to engage the surface of a battery being held within the battery holder of the dispensing device.