HK LCD Battery Detector 6S
Can be used in flight, or as a battery checking tool.   Accurate and easy to use, the Hobby King Battery Detector 6S  will give a warning buzzer when the Lipoly pack drops below 3.5V.   Unit includes reverse polarity detection, and a timing mode as well as total cell voltage.
Specifications
Battery :  1 ~ 6S Lipo / Li-ion / LiMn Volatage display resolution : 0.01V Voltage Dectection precision : 0.5%
Unit Voltage display range : 3.00 ~ 4.99V Total Voltage display range : 0.00 ~29.59 Current loading of test : 10mA Pins distance : 2.54mm Size : 64x36x6mm Weight : 20g   Note: Battery not included, only for illustration purpose.