GS GTX9-BS Maintenance Free Battery Dependable starting power with special lead alloy grids to reduce self-discharge Sealed, maintenance free design eliminates acid spilling and the need to check or refill the battery Gas recombinant technology eliminates water loss Absorbent Glass Mat (AGM) separators lowers internal resistance for faster recharging and higher performance Compressed plate packs protects against damage due to vibration and provides superior active material integrity which maximizes cycle life