Complete with Rubber o'ring. Replaces old cell with no adjustments.
Solid plate is easier to clean. The calcium just falls off. Of the time compared to mesh cathode. In a cathode they last longer (as they have up to 3 times more material than mesh). There is no problem with using them in place of a mesh cell.
The cell will be replaced in the first 2 years if any manufacture defects are visible.