Maintenance-free batteries with advanced Ca - Ca system. Long wet shelf life - no freshening charge required for up to 6 months from date of manufacture. Special paste formulation for positive and negative plates - higher life expectancy with superior charge acceptance in service, Double-clad polyethylene and glass mat separation - high reliability and longer life, Special Omega type cover design fitted with Venturi type chamber cover - excellent spill-resistant characteristics, Attractive cosmetics.