This unit is an AM transmitter assembled in a small tin box. It is designed to connect to the audio amplifier. On the right, the power switch and antenna wire can be seen. The transmitter is tunable from 1500 to 2000 KC.
Although it works as designed, it is effective only with a long antenna wire, or a very sensitive receiver. Note the two 3.3K resistors - if one is jumpered, then the power output is reduced. The 2N43 directly modulates the RF oscillator, so there is likely some FM component introduced as well.