A pressure reducing valve (PRV) is an automatic valve that lowers high-pressure fluid (like water, steam, or gas) to a lower, steady outlet pressure. It works without external power by using internal mechanisms, such as a diaphragm and spring, to automatically adjust the valve opening to maintain a constant downstream pressure, regardless of inlet pressure fluctuations or changes in flow. PRVs are vital for protecting systems and equipment, ensuring safety, and improving efficiency in applications ranging from residential plumbing to industrial processes.