When I'm flying LOS (Line Of Sight), I sometimes start to think I've been flying too long and may have my low voltage indicator set too low on my KK2 board. I then land it, disarm it, and read the voltage on the LCD screen. Sometimes I'm right and sometimes I it is okay and I just have more mAh left to fly. I looked on ebay and found these 5-30v LCD screen monitors for about $1.50. All they do is display the voltage of your battery. I put one on my tricopter based off Hall Studio's design and my other wooden bones tricopter. With these in place, I just need to fly close enough to myself to quickly see it and keep flying. You can see where I put in a short extension adapter so I can reuse this or move it on to future vehicles if I want to. Does anyone else use these or something different? Maybe I'm the only one that uses 3S and 4S batteries for flying.