A discharge assembly apparatus for discharging a metered volume of a liquid when used in combination with a liquid-containing, pressurised or pressurisable container, wherein the discharge assembly apparatus has: (a) an actuator assembly incorporating a valve stem adapted for movement from a first limit position to a second limit position, said valve stem having a discharge conduit arrangement with an inlet through which liquid is introduced into the discharge conduit arrangement and an outlet from which liquid is discharged from the apparatus; (b) a metering chamber formed within the valve stem and incorporating (i) a liquid discharge element which is moveable by fluid pressure from the container from a liquid primed position to a liquid discharged position to effect discharge of said metered volume of liquid and is moveable by a returning force from its liquid discharged position to its liquid primed position; and, (ii) an inlet/outlet arrangement for introduction of liquid from the container into the metering chamber and for discharge of liquid from the metering chamber; and (c) a housing wherein: (iii) the valve stem and the inner surface of the housing are arranged such that a fluid transfer passageway is defined therebetween, and (iv) the discharge conduit arrangement of the valve stem provides in the second limit position thereof communication between the outlet of the metering chamber and the outlet of the valve stem via said fluid transfer passageway, characterised in that the liquid discharge element is substantially spherical. (a) an actuator assembly incorporating a valve stem adapted for movement from a first limit position to a second limit position, said valve stem having a discharge conduit arrangement with an inlet through which liquid is introduced into the discharge conduit arrangement and an outlet from which liquid is discharged from the apparatus; (b) a metering chamber formed within the valve stem and incorporating (i) a liquid discharge element which is moveable by fluid pressure from the container from a liquid primed position to a liquid discharged position to effect discharge of said metered volume of liquid and is moveable by a returning force from its liquid discharged position to its liquid primed position; and, (ii) an inlet/outlet arrangement for introduction of liquid from the container into the metering chamber and for discharge of liquid from the metering chamber; and (i) a liquid discharge element which is moveable by fluid pressure from the container from a liquid primed position to a liquid discharged position to effect discharge of said metered volume of liquid and is moveable by a returning force from its liquid discharged position to its liquid primed position; and, (ii) an inlet/outlet arrangement for introduction of liquid from the container into the metering chamber and for discharge of liquid from the metering chamber; and (c) a housing wherein: (iii) the valve stem and the inner surface of the housing are arranged such that a fluid transfer passageway is defined therebetween, and (iv) the discharge conduit arrangement of the valve stem provides in the second limit position thereof communication between the outlet of the metering chamber and the outlet of the valve stem via said fluid transfer passageway, (iii) the valve stem and the inner surface of the housing are arranged such that a fluid transfer passageway is defined therebetween, and (iv) the discharge conduit arrangement of the valve stem provides in the second limit position thereof communication between the outlet of the metering chamber and the outlet of the valve stem via said fluid transfer passageway,