IMPORTANT NOTE: The T-Cell-15 is the only replacement cell that will work on your existing Salt Generator System if your system was installed before 2009. For example: You cannot downgrade to a T-Cell-3 or a T-Cell-9 if your system originally came with a T-Cell-15 without upgrading your control panel/motherboard. T-CELL-3 & T-CELL-9 Goldline Cells are NOT COMPATIBLE with systems Manufactured before 2009. Requires software revision 1.5 for AquaRite & 4.2 for AquaLogic or greater to be compatible.