L: 350 x W: 167 x H: 179 (mm) The rechargeable batteries are ead- ead dioxide systems. The di ute su furic acid e ectro yte is absorbed by separators and plates and thus immobilized. Should the battery be accidentally overcharged producing hydrogen and oxygen, special oneway valves allow the gases to escape thus avoiding excessive pressure build-up. Otherwise, the battery is completely sealed and is, therefore, maintenance-free, leak proof and usable in any position.