Portable dieital battery meter：

  The baeery meter weighs only 5.8g and is very useful when flying outside. It can detect the Lithium battery voltage from 1-any cells with an accuracy of 0.03V on a cell by cell basis.it can also indicate the total votage in the battery pack,which is very convenient for users when you want to quickly check the status of the status of the pack(charged and ready to fly,or not).this device can be used as a hand held device or you can fit one to every model with a small piece of double side serno tape