Conductivity/TDS 3 Sensor Input Module & 3 Range Switch Combined with Enclosure is an accessory for 750 Series II Conductivity/TDS Monitor/Controllers. The 3SR will function with all Conductivity/TDS models, analog or digital. The 3 Sensor Switch allows the user to view 3 separate sensor locations and to set the alarm/control function using only one Monitor/controller. The 3 Range Switch allows the user to select which "range" (Cond/TDS = X1, X10 or X100) to view, and to set for alarm/control function.