A dispenser for dispensing a product from a pressurized product container comprising a housing defining a user port and adapted to have a pressurized product container mounted therein, the pressurized product container having a dispensing valve movable relative to the container between an open and a closed position; the housing further comprising a rolling member comprising a vane, and two associated rolling surfaces, the rolling member being capable of rotation in contact with the rolling surfaces such that they translate in opposite directions relative to the rolling member in response to inhalation through the user port, the rolling member being rotatable between a locking position in which the rolling member directly or indirectly engages the pressurized product container or valve to maintain the valve in the closed position, and a release position in which the valve and the pressurized product container move relative to each other so that the valve moves to the open position to dispense product from the container and towards the user port.