Why allocate more time and money than necessary to balance heating and cooling systems. Just set the flow and the Flo-Setter™ II valves do the rest. The gpm dial is unique and easy to set. Once set, no adjustments are required even if the pressure varies or the system is changed. It is as simple as it gets. The Circuit Sentry™ Flo-Setter™ II valves are easy to install and maintain set flow rates even when installed next to a pipe bend or fitting. The easy to read gallons per minute scale on the lockable handle ensures that the flow setting is simple and user friendly while the integral P/T plugs allow verification of required differential pressure.