Flow Regulators A flow regulator is a component that maintains a predefined constant flow rate independent of the prevailing line pressure. It automatically compensates for pressure variations between 15 and 100 psi. NEOPERL® flow regulators are thus known to be pressure compensating. Neoperl® flow regulators are designed to be used inline in clear water applications such as faucets, showerheads and handles, instantaneous water heaters, filters and appliances, however there are some special applications in which they are used. Pressure compensating flow regulators are not recommended for use in non-pressurized systems. There are several styles and sizes to choose from in a large range of flow rates. Some models are rated in liters per minute with defined upper and lower tolerances (usually +/-10% to +/- 20% but this varies depending on the flow rate. Lower flow rates have larger tolerances), while other models known as US models are rated in US gallons per minute with a defined upper tolerance of +0 and a defined lower tolerance depending on the flow rate. Many models carry worldwide certifications including NSF 61 and several help to meet WaterSense and LEED requirements for faucets, showerheads and handles. Select models, if mounted properly meet the 8 lb pullout force required by ANSI for showerheads and handles.