You could have searched for DMD on the forums...dozens of posts would have shown up!
DMD = Dual Mode Damper
It is a redesigned crank pulley that dampens possibly destructive crank vibrations. The theory is that crank whip due to harmonics causes the rod end bearings to spin. Buh bye bottom end, hello new engine.
They normally run $98 + shipping, so the deal today at $89 shipped was a good deal.
Since you have an auto, you don't need one. The torque converter does a good job of dampening.
-Lance
