The Odyssey PC1200 batteries that Kodiak Industries includes are military spec and come with metal-jacketed cases. This metal jacket protects and insulates the low resistance, pure virgin lead plates and helps to maintain rigidity within the battery. Filled with a state-of-the-art compressed glass mat material separating each of the lead plates, the Odyssey PC1200 is built for the most extreme of uses. Each PC1200 battery contains about one tablespoon of laboratory-grade sulfuric acid that is absorbed right into the mats, which is why all Odyssey batteries are classified as dry cell batteries. We like that these batteries are able to survive high vibration environments and multiple high discharges thanks to their robust design.