Welcome to our shop! This active buzzer module is designed with convenience and functionality in mind. It has an internal oscillation source, ensuring that it will alarm as long as it is energized. With convenient program control, you can easily make it sound with a high or low level from a single chip microcomputer, making it better than a passive buzzer. The module is driven with a 9012 transistor and comes with holes for easy installation using a bolt. The module can be externally connected to a 3.3V-5V voltage, making it compatible with both 5V and 3.3V micro-controllers. Additionally, it has an external connection for GND3 out external micro-controller IO port. Specifications: - Working Voltage: 3.3V-5V - Module Interface: 3 wire system - Size: 3.8*1.3cm/1.5*0.5in - Quantity: 5pcs - Weight: 4g (approx.) Package Includes: - 5 x Buzzer Modules 100% Satisfaction: Our customers are our top priority. If you find any product problems after receiving the goods, such as damage and incorrect quantity of goods, please contact the seller immediately. We try our best to provide you with satisfactory after-sales service.