Model B Sustainiac like the one George Lynch used on Back For The Attack. If your a Lynch fan you will dig it. Unit works great and has a newer smaller transducer that clamps on to your headstock with a 15ft. long cord. It also comes with the original transducer and metal headstock mount and instructions. It vibrates the headstock to produce sustain indefinitely. These units are getting hard to find. $300.00+40 shipping.