Item Type: Active Buzzer Module Material: PCB Purpose: DIY Alerter Operating voltage: 3.3V-5V Fixing method: bolt hole and screw fixing Operating Voltage: 3.3V-5V Fixing Method: Bolt hole and screw fixing PCB Size: Approx. 3.3cmx1.3cm/1.30inx0.51in Package List 5 x Active Buzzer Module 1Function: Active buzzer module has internal oscillation source, will alarm as long as being energized. 2High Level Trigger: Active buzzer alarm module with high level trigger and continous sound output. 3High Quality Material: Buzzer module is made of high quality PCB material, wear resistant, lightweight and durable. 4Compact Size: The size of buzzer alarm sound module is approx. 3.3cmx1.3cm/1.30inx0.51in, compact and easy to carry. 5Easy Installation: Designed with holes for fixing with bolt, easy to install, convenient for using, save your time and energy.