A wide variety of actuator types may be employed to provide synchronized vibration, including linear actuators, {TAIL ~ rotary actuators}, rotating eccentric mass actuators, and {HEAD ~ rocking mass actuators} 
A wide variety of actuator types may be employed to provide synchronized vibration , including linear actuators , { TAIL ~ rotary actuators } , rotating eccentric mass actuators , and { HEAD ~ rocking mass actuators }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD