The buzzer has three modes:1.It is compatible with the functions of the traditional buzzer and is synchronized with the driver of the flight controller. 2.When the flight controller is connected, if the main battery is powered off during the flight, it can still trigger the buzzer to alarm 30 seconds after the power is off, and give an alarm sound of 100 decibels, and the LED light flashes at the same time. 3.long-time alarm function (30 minutes after powered on), is off by default, it can be activated by resoldering the wires to different pads. 4.When the flight controller is connected normally, the buzzer will be triggered automatically when the power is on for 30 minutes, and the alarm sound of 100 decibels will be emitted, and the LED light will flash; Press and hold the release button for more than 5 seconds to turn off the buzzer alarm and LED. 5.HGLRC Soter is compatible with all Betaflight and Cleanflight flight controllers. Just connect to the buzzer interface of the flight controller and it will work. When the flight controller wiring is correct, the multi-rotor aircraft is powered on and the flight controller power supply will automatically charge the HGLRC Soter ( Red LED flashing indicates that the buzzer is being charged, red LED off means charging is complete.) Item Name:HGLRC Soter buzzer Input voltage:5V Size:22mm x 12mm x12mm Weight:3.6g Colour:Black Material:composite materials Package Contents: 1 set x FPV Drone Buzzer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.