The Hobbyking 2-8S Cell Checker with low voltage alarm features loud twin piezo alarms to notify you once your cells reach a user defined voltage. You can customize the alarm to sound at a voltage between 2.7v~3.8v per cell in 0.10v increments by pressing the setting mode button.This unit also features a handy built in LED display that will show the voltage of each cell followed by the overall voltage of the pack.Don¡¯t risk your model by flying on depleted batteries, at this price piece of mind flying can't be any cheaper!Specifications.Input: 2~8SBattery type: Lipo/LiFe/Li-ionCell Voltage Display Range: 0.5v~4.5vTotal Voltage Display Range: 3.7~36vAlarm set values: Off or 2.7~3.8vSize: 41x25x10mmWeight: 9g