The present invention provides an enclosed aerosol source comprising an assembled combination of the aerosol source combination as such and an enclosure:• the aerosol source having:• a canister,• a spout at one end of the canister, the spout being movable inwards of the canister for substance release,• a spring urging the spout outwards of the canister with a force required to be overcome for release movement inwards, and• a valve for releasing a substance from the canister on longitudinal movement of the spout against the spring and• the enclosure having:• at least one dispense-mechanism, positioning feature at a determined position and• an adjustable location for the canister, the location being adjusted to provide a determined position of the spout with respect to the dispense-mechanism, positioning feature, when the aerosol canister has been assembled into the enclosure,the arrangement being such that on movement of the spout through determined stroke with respect to the dispense-mechanism, positioning feature and against the spring substance release is predictable
