The UPG UB12900 (12 Volt 90 AH) Group Size 27, Sealed AGM battery is a non-spillable state of the art design battery. There is no need to add electrolyte or water, as gases generated during charging are recombined in a unique "oxygen cycle. This battery can be mounted in any position, requires no maintenance and may be transported by Air or Ground without any special handling regulations. When an AGM battery is charged no hazardous fumes escape the battery case, gases are processed within the battery itself.