Batteries

Lead Acid, Lead Antimony, Maintenance Free, Sealed Lead Acid, AGM (Absorbed Glass Matt), EFB (Enhanced Flooded Battery), Calcium, Calcium / Calcium, Gel - these are all batteries that contain lead and acid and form a class of battery referred to lead acid batteries. Another example might be Lithium batteries and all their variants.

Each of these battery variations has been designed for a specific application/purpose. But many applications can take advantage of these characteristics so this is why you end up with batteries being used for starting applications even if they were primarily designed for Ah storage bank applications like house batteries in a boat or motor home.