Sealed Lead Batteries (Rechargeable) Rechargeable batteries are lead-lead dioxide systems. The dilute sulfuric acid electrolyte is absorbed by separators and plates and thus immobilised. Should the battery be accidentally overcharged producing hydrogen and oxygen, special one-way valves allow the gases to escape thus avoiding excessive pressure build-up. Otherwise, the battery is completely sealed and therefore maintenance-free, leak proof and usable in any position. Stable quality and high reliabllity Sealed construction Long services life, float or cyclic Maintenance-free operation Low pressure venting system Heavy duty grids Low self discharge UL component recognition 7.0Ah