The X4 comes with a control unit which has a very long cord that plugs into a GFCI wall socket. The control unit has a 4-button control panel from where you will power the robot and select your preferred cleaning setting. There is also a “Dirty Filter Indicator” on the control panel which comes on when the filter baskets are full and ready to be emptied. When this light comes on, the robot stops working until the filters are emptied, cleaned and replaced.