This is a Xadow module which can emit a tone. To drive it, you need to control two pins simultaneously: this is different from Grove - Buzzer which uses one pin for control. It is petite but LOUD! It can be used for making beeps, tones and alerts.
Xadow is a though small but perfectly formed Arduino compatible board series containing several modules. It is suitable for space-sensitive projects such as wearable devices and arts designs, which have limitations on size, weight and flexible cascade connection.