THE SEM-900 is the microphone contact of professional use, the most compact on the market. You have simplified all the components including the battery, to reduce the maximum size without showing diminished performance.
The SEM-900 has an audio output so that you can make the recordings from a simple and easy manner. Its sensitivity is very high. Very easy to use.
Note: do Not hit or drop the microphone from contact with the wall. You could cause permanent damage to the device. It is not resistant to water. Please, do not submerge or immerse the device.