Powersonic PS-640F1 - 6 Volt/4.5 Amp Hour Sealed Lead Acid Battery with 0.187 Fast-on Connector The valve regulated, spill-proof construction allows troublefree, safe operation in any position. There is no need to add electrolyte, as gases generated during overcharge are recombined in a unique "oxygen cycle." Batteries may be used in series and/or parallel to obtain choice of voltage and capacity The high impact resistant battery case is made of nonconductive ABS plastic to UL94-HB Power-Sonic batteries may be discharged over a temperature range of -40C to +60C