This is a under-voltage switch controller used to turn off the power of load in the event of the voltage dropping below a set value. When the battery voltage increases to a set value, the module automatically turn on load again. Designed with a LED indicator to show if battery is under-voltage. Both turn-off and turn-on voltage value can be adjusted by simply pressing buttons. This controller help you to battery from over-discharging and prolong battery life. Suitable Battery: 12V storage/lithium battery Control Current: 20A Control Precision: 0.1V Voltage Error: +/- 0.1V Colour: as shown Material: ABS Size: 7.9 x 4.3 x 2.7cm Package Contents: 2 x Electronic Controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.