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 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 be triggered automatically when the power is on for 30 minutes, and the alarm sound of 100 decibels be emitted, and the LED light flash; and hold the release button for more than 5 seconds to turn off the buzzer alarm and LED. 5. Soter is compatible with all Betaflight and Cleanflight flight controllers. Just connect to the buzzer interface of the flight controller and it work. When the flight controller wiring is correct, the multi-rotor aircraft is powered on and the flight controller power supply automatically charge the Soter ( Red LED flashing indicates that the buzzer is being , red LED off means charging is complete.) Item Name: 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.