It keeps them moisturized & soft.  Without it, they would get too hard to wear after 2 weeks & be prohibitively expensive to replace.  All it is is a Hextronik D7xx motor rewound with 70 turns in a Y pattern to increase the torque.  A microcontroller & 2 BJT's bang 2 of the phases to shake the lens case.  The 3rd phase is permanently 12V.  An LM317 drops 19V from a laptop power supply to 12V, releasing heat which warms the case.  The heating is another requirement for good results.  Because of the limited control of 2 phases, the timing of the shaking has to match the system's resonant frequency.  Aluminum draws heat away from the motor.

An important note is the shaking does tear apart brand new lenses.  A 3 hour timeout was added to keep them intact.   A proper 3 phase motor controller would allow slower shaking & probably do a better job, but it's just a stupid agitator.