4 pin microphone SMD pinout indentification
It seems that this microphone if from a cell phone. It is hard to tell by the picture whether it is a condenser mic or MEMS mic. My guess it is a condenser microphone.

Usually the largest pad(s) is shield. You can assert this by using a multimeter to check if the two bottom pads are connected (0 ohms).

In case of a condenser mic, the top two pads would be the element.