... Calcium-Calcium,Lead acid Battery. 3 Long life,Powerful Design. Maintenance Free Automotive Battery.Available Capacity from 36Ah-150Ah. 1.Long life ... corrosion, so as to prolong the battery life remarkably.2. Completely Maitenance Free ,Never need to add water--Water recombined technology, makes ... the danger by automatically reducing the current to near zero. Maintenance Free Battery