Abstract: A pressure relief valve of the type primarily designed to regulate the flow of fluid generally in the form of air and its rate of flow and capability of being utilized in combination with a sphygmomano-meter assembly whereby flow of fluid from the sphyg head is accomplished at a predetermined rate and is selectively regulated by manual manipulation of the valve assembly. A valve housing is movably mounted therein and a valve block which is disposed to establish fluid communication from a sphyg head or point of use of the fluid through a metered port so as to establish a flow path for the fluid exiting from the valve assembly at a predetermined rate.