The YB41X fixed proportional pressure reducing valve, professionally produced by Shanghai Shuangheng Valve Co., Ltd., has a beautiful appearance, reliable quality, accurate proportion, and smooth operation, reducing both dynamic and static pressure. The fixed proportion pressure reducing valve utilizes the differential pressure generated by the different cross-sectional areas of the piston at both ends inside the valve body to change the pressure behind the valve and achieve the purpose of pressure reduction. The fixed ratio pressure reducing valve has pressure reducing ratios of 2:1, 3:1, 4:1, 3:2, 5:2, etc., and different ratios of pressure reducing valve products can also be designed according to user requirements.