YB43(1)X fixed ratio proportional pressure reducing valve should be composed of valve body, imported flange, piston, large cylinder liner, small cylinder liner, outlet flange and O-ring, sealing gasket and other parts. The proportional pressure reducing valve uses the different cross-sectional areas of the floating piston at both ends of the valve to form the pressure difference between the valve front and the valve, and change the pressure after the valve to achieve the purpose of pressure reduction. Proportional pressure reducing valve has unique structure, superior performance, large flow, stable switching, no noise, stable pressure reduction ratio, that is, "reducing pressure" and "reducing static pressure", and has the effect of reducing or even eliminating the damage of "water hammer" phenomenon to pipe fittings and water supply appliances, eliminating unnecessary vibration, saving water sources and protecting the pipe network.