Transducers produce sound through direct vibration of the bones in the head or are capable of converting surfaces into 

speakers via vibration when placed on materials such as desks, walls, doors, and many other materials.

These are special speaker drivers that attach to surfaces causing them to vibrate with the 
audio signal. Uses include audio from windows, wall panels.  

Specification:

                    Application                Full-Range Exciter

                    Impedance                  8 ohms

                    Power Handing(RMS)         20 Watts