GPC-1005B-R is a low voltage disconnect. It disconnects the load if the voltage drops below a predefined threshold. It reconnects the load when the voltage recovers. Ten threshold options set by rotary selector. For 12V battery: 2, 9.3V; 3, 9.7V; 4, 10.1V; 5, 10.5V; 6, 10.9V; 7, 11.3V; 8, 11.7V; 9, 12.1V For 24V battery: 2, 18.6V; 3, 19.4V; 4, 20.2V; 5, 21.0V; 6, 21.8V; 7, 22.6V; 8, 23.4V; 9, 24.2V. When switch is at 0, OFF: Disconnect power from the load. (When rotated to location 2~9, the switch will stay off until reconnect threshold is reached.) When switch is at 1, ON: Connect power to the load if there is no pending fault.