<p>The present invention is directed to a valve used in both conventional and bag-on-valve aerosol container applications that allows a high flow rate of especially viscous substances. Valves according to the present invention include a valve housing, a valve stem, and a spring or other biasing device that allows the valve stem to move relative to the valve housing. The valve stem is hollow to allow the flow of product to and from a bag attached to the valve housing. There are radial bores and a seal near the bottom of the valve stem that dictate the passage and flow rate of pressurized product between the product container and the environment. The bore shape and size can be selected to facilitate a high volume flow rate for highly viscous substances.</p>