Hobby King Audio Battery Monitor 3S, New in Package | eBay
JEGS 45030: Low Voltage Monitor | 2S-8S LiPo Batteries | Monitors the Pack Voltage & Individual Cell Voltage | LCD Display | Low Voltage Alarm | Adjustable Alarm from 2.7V to 3.8V
Hobbyking Battery Monitor 3S
Ovonic 3000mah 4S 14.8V 35C Lipo Battery EC3 Plug for Airplane & Heli – Ampow