Product Review

The link to User Manual: http://www.mateksys.com/downloads/DBuz5V_Manual_EN.pdf

It can be used on triditional PWM receivers or FPV racing flight controller.
The tiny buzzer is drived by on board MCU. It can output louder sound than 5V active buzzers.

Specification:
Brand name: Matek
Item name: 5V Loud Buzzer
Built-in MCU
Working voltage range: 4.5-5.2V DC
Power: 1W Max.
Sound Output: 90dB Max.
Size : 18x13x8mm
Weight: 2g

Package Including
1 * Matek 90dB Lost Model Beeper Flight Controller 5V Loud Buzzer Built-in MCU for FPV Multicopters Quadcopter