ACDelco Gold (Professional) Automotive AGM 36 Month Batteries have high cycling capabilities, are remarkably charge-receptive, and are necessary for ‘start/stop’ vehicle applications. The Absorbed Glass Mat design is 100% leak and spill proof because the Electrolyte is permanently held in the glass mat separator instead of free flowing within each cell. Oxygen recombination minimizes water loss and reassures maintenance-free performance. ACDelco Gold (Professional) Automotive AGM 36 Month Batteries also have a 36 month Free Replacement Period. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.