FrSky Voltage Monitor, with OLED screen

Well this is rather nifty... a voltage montor that shows 1-6 cells on an OLED!  It's from FrSky and designed to be part of their telemetry system, but works fine on the ground as a voltage meter.  Not bad for less than $12... I had no idea OLEDs were so cheap!

FrSky 1-6 cell voltage monitor