Includes Rheostat, Reverse Action Pressure Switch, Mounting/Junction Box, Control Knob, 18/2 Shielded Wire and connectors. Compatible with Grundfos SQE pumps using CU301 control box. The "Full Kit" option is for installations that supply water to the Open Loop(Pump & Dump) Geothermal unit and domestic water and require a check valve, secondary pressure tank, tank tee and accessories that must be purchased separately . The "Less Reverse Action Pressure Switch" option is for SQE pumps that are dedicated to just Open Loop(Pump & Dump) Geothermal units to enable a pressure setting lower than the 40 PSI lower limit of the CU301 control.