Function: This active buzzer has an internal vibration source, so it will alert you as long as it is connected. Convenient program control, high and low levels of single chip microcomputer provide better sound than a passive buzzer. The module is driven by a 9012 transistor. It has a bolt on hole for convenient installation. External connection of 3.3V-5V voltage can be directly connected to 5V microcontroller and 3.3V microcontroller. External connection of GND3 output microcontroller IO port Specifications: Operating Voltage: 3.3V-5V Module Interface: 3-wire system Size: 3.8 * 1.3cm / 1.5 * 0.5in Quantity: 5pcs Weight: 4g (approx) Package Content: 5x Buzzer Module