Product review (5 stars): There are two of these dampers inside the control unit and the upper unit was bad. The gears were stripped on the worm drive ...
This was the corrrect part for my GE frig - ZISS420NXASS.  There are two of these dampers inside the control unit and the upper unit was bad.
The gears were stripped on the worm drive and it was making what some call a "machine gun" noise intermittently. I will telll that it took a couple  of hours to replace. One needs to take out the lower drawers in the frig and unhook all of the wires that go to the lower control panel for the two lower drawers. Take note of where all of the connections go when disassembling. Almost all of the wires are color coded and keyed which helps.
i did not purchase a new gasket - WR60X10116 which I wish I had. Do this when you replace either of the dampers in the control / fan unit.
One final note - the GE parts list for this frig lists only one damper, but there are two as noted above.