Weathermatic® CombiFlow SLF-COMBIFLOW-100 Flow Processor, is a unique signal controlled device that conditions and scales the signals from two digital flow sensors and combines them into one scalable digital output. The SmartLink® Flow Aircard then perceives the signal is coming from a single flow sensor. It is compatible with the SLFSI Series Flow Sensors and most other sensors producing a square or sine wave output proportional to the rate of flow.