The Pressure Reducing Valve (OEM Part No. 3128201985) is a replacement hydraulic control component used on Epiroc / Atlas Copco Boltec 235, Boltec 235H, Boomer K41 and Simba H157 mining and drilling equipment. It is designed to reduce and regulate hydraulic pressure supplied to downstream circuits, helping maintain a controlled operating pressure for associated hydraulic functions. Stable pressure regulation supports smooth actuator movement, protects hydraulic components from excessive pressure and contributes to reliable operation of the machine hydraulic system. The 3128201985 Pressure Reducing Valve is suitable for routine maintenance and replacement when the original valve develops internal leakage, unstable pressure control, sticking or other hydraulic performance problems. Public parts documentation identifies this part as PRESS.RED.VALVE, with installation associated with the boom panel on certain models.