Can be configured to be used as one of the following battery saving products:Timer Disconnect 12V signal triggers relay to connect battery power to devices When signal is removed the timer is activated and will disconnect devices after a preset time Timer ranges from 15 minutes to 4 hours Low Voltage Disconnect Senses low battery voltage and automatically disconnects devices Low voltage setting can be used in conjunction with Timer Disconnect. Low voltage will disconnect devices prior to preset time to preserve battery power Automatic Charging Relay Automatically combines 2 batteries for charging, isolates them when discharging Single side sensing design only monitors the voltage of the start battery Ideal for AGM auxiliary batteries or batteries larger than the start battery Solenoid12V signal will connect or disconnect relay without any time delay