Available pressure regulators are considered too heavy for application in pneumatic prostheses. Goal of this paper is developing a lighter pressure regulator adapted for this speci?c application. We present an ultralight mechanical pressure regulator with several possible con?gurations as well as an optimization strategy for easy adaptation of the designs to slightly differing requirements. Our system functions using a con- ventional piston-valve con?guration and can be used with either mechanical or gas spring. Dependent upon the con?guration the pressure regulator can either use disposable CO2 -cartridges or an integrated gas-storage container for gas storage. The pressure regulator performance of both the spring and pressure controlled con?gurations are evaluated for air?ow stability and suf?cient pressure recovery. The results have shown stable outlet pressure for both the pressure and spring controlled con?gurations.