Originally Posted by: crazyguyDigitech Whammy should be mentioned at this point. Other than that I'd say it's all high-output pickups and insane distortion from the amp. Actually, the hard part (at least for me) is sustaining the harmonic while bending it as long as he does. I guess it depends mostly on the quality of your tremolo.

As you said, its from high output pickups, loads of gain, but also Dime used neck-through bodies which makes the notes sustain a lot longer compared to a bolt on or set neck (though I've heard people say they've played set necks that sustain longer than neck-through's)