The Restriction Assembly is designed for use on large pneumatic pilot lines in conjunction with an air maintenance device. The restricted orifice limits flow into the release system. This prevents rapid pilot line pressure build up after the release devices have operated. The standard 0.031” (0,79 mm) orifice (marked “C” on wrench flat) is for use with the Viking Model C-1 or Model C-2 Thermostatic Release, Model M Fixed Temperature Release, and Pilot Head release systems.