Absorbed Glass Mat (AGM) Technology is an advanced battery design used in Yuasa's Maintenance Free Batteries that eliminates water loss. Comes filled with acid and the battery is permanently sealed - so you'll never need to fill it with water or check the acid level. Long Life Because of its lead calcium design, the AGM battery will hold its specific gravity more than three times longer than conventional lead antimony types. This means much longer periods between charges when the battery is used in a standby mode, like winter storage.Sealed, Non-spillable The AGM battery is virtually maintenance free. It's totally sealed and all of the acid is absorbed in the special plates and separators, so there is no need to worry about acid leaks on valuable vehicle parts and accessories. The simplest battery to install, as the battery is filled, sealed and charged at the factory. Battery is ready for installation right out of the box. Additional plates inside battery provide up to 30% more power than the Submicron battery. High level of power (cranking amps) possible for today's big bikes. Never needs refilling, but may need periodic charging. Includes 1-year manufacturer's warranty.