64 Series adjustable regulators usually reduce tank pressure to an intermediate pressure for use by another regulator. They may be used as high-pressure regulators on distribution systems when used in conjunction with first-stage downstream regulators. When equipped with an internal relief valve (64SR Series), the regulator may be used as a final-stage regulator on high-pressure systems. 64KB Series has a special PTFE diaphragm protector that makes it suitable for anhydrous ammonia NH3 service