Description This product is designed for monitoring 1S-8S lithium batteries and helps protect the battery from overheating and over-discharging. It automatically detects the voltage of each battery cell and supports reverse connection protection. The factory default voltage setting is 3.3V. Press the button to adjust the voltage threshold, and the device will automatically save the new setting.Features - Color: As shown in the pictures - Material: Electronic components - Size: Approx. 4 x 2.5 x 1 cm / 1.6 x 1 x 0.4 inch (L x W x H) - Designed for use with 1S-8S lithium batteries - Automatically monitors individual cell voltage and provides reverse polarity protection - Enables real-time monitoring of battery status to prevent overcharge and over-discharge - Red LED flashes and buzzer sounds when voltage drops below the set threshold - Default setting is 3.3V; adjustable via button press with automatic setting retention Packing List 1 x Lipo Battery Low Voltage Tester Checker 1-8S Buzzer Alarm with LED Indicator for RC Helicopter Quadcopter