The cheaper solution to store power. Although some models are lorry and truck battery look-alikes, their internal structure has nothing to do with an automotive battery. Specially designed for deep cycle use. ideal for the smaller solar setup.
AGM (Absorbent Glass Mat) are maintenance free batteries. They were designed in the 80's for military aviation use. AGM batteries give and absorbe more electric currente than other sealed batteries. They can be used with normal charging parameters and don't need special chargers.
The OpZS batteries are just about the best option battery you can purchase for a decent solar setup. They are extremely long lasting when correctly sized, charged and looked. Although the initial purchase is more expensive than monoblocks, they work out a lot cheaper on a long term.