Using oxygen recombination technology: maintenance-free. PbCaSn alloy for plate grids: less gassing, less self-discharging. High quality AGM separator: extend cycle life and prevent micro short circuit. ABS material: increase the strength of battery container. (Flame-retardant ABS is optional). High purity raw material: ensure low self discharge rate 6.Silver-coated copper terminals brass insert terminals and lead terminals improve the electric