... ,ISO14001,ISO/TS16949,CE,SASO.SONCAP etc1.The maintenance free battery is made from silver alloy grid and have better function ... for long storing after electrification, (6)con-venient fixing for users having no chance to touch acid liquid, (7)no tempature rising ... ,recombination of oxygen and hydrogen,and no liquid or gaseous acid comes into being and no pullution to environment. lead acid car battery