The biggest issue with many drag systems is that they are not smooth at the beginning of the drag.
ATD or Automatic Tournament Drag is the newest introduction into DAIWA spinning reels. On one level ATD implements structural changes to the spool metal of the reel that provides greater support of the spool across the entire length of the main shaft.
This additional support of the spool reduces spool twist under load, promotes more even pressure on the drag washers and ultimately reduces "pulsing" of the drag when fighting the fish.
ATD - An other milestone of reel technology!