The output is an A.C. signal of between 5-10mV. In most cases the output will need to be connected to an Audio Amplifier to boost the signal to a useable level.
The microphone is fairly small. It has 2 solder pad connections on the underside. One of them is connected to the case. This connection is the 0v connection.
Sometimes there are wires already attached to the solder pads.