A valve for use in a valve assembly, the valve configured to dispense a predetermined metered dose of product from a container upon actuation of the valve, the valve comprising: a housing having a hollow cylindrical body with an open top end, a planar base, an outer surface, and an aperture through the planar base; a dose chamber having a lower cylindrical body portion with an open bottom end and an upper cylindrical body portion with an open top end, wherein the upper cylindrical body portion projects from the lower cylindrical body portion along a vertical axis, wherein the upper and lower cylindrical body portions (152, 154) are in fluid communication via an aperture through the vertical axis, and wherein the upper cylindrical body comprises an annular disc member projecting radially therefrom; an annular gasket seated at the open end of the upper cylindrical body; a valve stem with a bore in a top portion thereof defining an upper passageway along the vertical axis, a bore in a bottom portion thereof defining a lower passageway along the vertical axis, a first horizontal orifice through the stem communicating with the upper passageway, and a second horizontal orifice through the stem communicating with the lower passageway, wherein the stem is axially displaceable along the vertical axis and is biased by a spring in the upper cylindrical body portion so that a portion of the stem projects through the annular gasket; a sealing element disposed about an outer circumference of the lower passageway below the second horizontal orifice; a piston disposed in the lower cylindrical body and biased against the planar base by a spring and an upper end of the lower cylindrical body; wherein the dose chamber comprises a first horizontally disposed aperture and a second horizontally disposed aperture, wherein the first horizontally disposed aperture is below the disc member to provide fluid communication between the housing and the upper cylindrical body portion, wherein the dose chamber is disposed in the housing so that the disc member seals the open top end, and a sealing member disposed about an outer circumference of the lower cylindrical body portion to cover the second horizontally disposed aperture, wherein the stem is displaceable along the axis to dispense the predetermined metered dose of product. a housing having a hollow cylindrical body with an open top end, a planar base, an outer surface, and an aperture through the planar base; a dose chamber having a lower cylindrical body portion with an open bottom end and an upper cylindrical body portion with an open top end, wherein the upper cylindrical body portion projects from the lower cylindrical body portion along a vertical axis, wherein the upper and lower cylindrical body portions (152, 154) are in fluid communication via an aperture through the vertical axis, and wherein the upper cylindrical body comprises an annular disc member projecting radially therefrom; an annular gasket seated at the open end of the upper cylindrical body; a valve stem with a bore in a top portion thereof defining an upper passageway along the vertical axis, a bore in a bottom portion thereof defining a lower passageway along the vertical axis, a first horizontal orifice through the stem communicating with the upper passageway, and a second horizontal orifice through the stem communicating with the lower passageway, wherein the stem is axially displaceable along the vertical axis and is biased by a spring in the upper cylindrical body portion so that a portion of the stem projects through the annular gasket; a sealing element disposed about an outer circumference of the lower passageway below the second horizontal orifice; a piston disposed in the lower cylindrical body and biased against the planar base by a spring and an upper end of the lower cylindrical body; wherein the dose chamber comprises a first horizontally disposed aperture and a second horizontally disposed aperture, wherein the first horizontally disposed aperture is below the disc member to provide fluid communication between the housing and the upper cylindrical body portion, wherein the dose chamber is disposed in the housing so that the disc member seals the open top end, and a sealing member disposed about an outer circumference of the lower cylindrical body portion to cover the second horizontally disposed aperture, wherein the stem is displaceable along the axis to dispense the predetermined metered dose of product.