The Cla-Val Model 343GF/348GF Hose End Pressure Control Valve (HEPCV) is a direct-acting pressure regulator.  t is designed for use in aircraft refueling to protect the receiving aircraft from excess pressure and damage due to pressure surges. It is bolted to a Cla-Val Model 341GF or 347GF Aircraft Refueling Nozzle at the end of a delivery hose or a Pantograph used to refuel jet aircraft under pressure.