The recombinant gas RG Series VRLA-AGM batteries are known for superior starting power with quick, cool operation in all conditions without the threat of thermal runaway. Less initial cost than NiCd, no deep cycling, and maintenance free design reduces operating costs per hour. Concorde recombinant gas valve regulated lead acid batteries for engine starting, emergency / essential power, and standby power applications are constructed with cutting edge Absorbed Glass Mat (AGM) technology. Concordes proprietary PolyGuard Microporous Polyethylene Separator shields the positive plates against shorting, shock or vibration. No other manufacturer offers this dual layer insulation protection feature.Certified nickel cadmium battery replacementReliable essential power in the event of a generator failureLow impedance designMaintenance freeConstructed with non removable vent valves - no addition of electrolyte or water requiredAerobatic: Non spillable at any altitude or attitudeFactory tested to assure airworthinessShipped fully chargedRG Series batteries ship HAZMAT EXEMPTRG-390E/LS is a fireproof, stainless steel battery with side vent tubes of polypropylene and fabric lifting straps