Features 1、This is a under-voltage automatically charging controller used to charge storage battery in the event of the voltage dropping below a set value 2、When the battery voltage increases to a set value, the controller will automatically stop charging 3、Designed with a LED indicator to show if it is charging 4、Both under-voltage and over-voltage value can be adjusted by simply pressing buttons 5、This controller will help you to protect battery from over-discharging and prolong battery life Specification Features: Designed with a LED indicator to show if it is charging. This controller will help you to protect battery from over-discharging and prolong battery life. Specifications: Suitable Battery: 12V storage/lithium battery Control Current: 20A Control Precision: 0.1V Size: 7.9*4.3*2.7cm/3.1*1.7*1.1in Weight: 40g(approx.) Restore to Factory Setting: At normal state, press and hold S1 and S2 buttons together, till display shows 888, to restore to factory setting. Package Includes: 1 x Battery Charging Controller Package List