all fit in one unit, stable, reliable solar working station with circulation Pump, controller, flow meter... IntroduceSuitable for: Suitable for Split and ... speed controlling)Digital flow meterOHQM OHQM Thermal energy measuringINTV INTV Pump interval fucntionAuxiliary function: a, heating return rising, b. ... SR961 for split pressure solar water system,controller, circulation pump,pressure meter unit