12 V 7 Ah - 200 Ah Univercell batteries are all rechargeable, highly efficient, sealed and maintenance-free. The Univercell battery is known for its stability and reliability. It is maintenance-free and has the necessary materials for safe and proper operation. The battery is resistant to overcharging, over-discharging, vibration and arrows. It is also capable of long storage. Univercell battery has a unique structure and leak-proof feature. With this feature, Univercell battery provides efficient and safe applications in any situation. Univercell dry batteries have the sealing and non-fluidity properties required in air transportation. There is no need to check the specific gravity of the batteries and no need to add water to the batteries during runtime. None of these maintenance procedures apply to Univercell fully maintenance-free dry type batteries. Univercell batteries are equipped with a low pressure and safe ventilation system from 1 to 6 psi. Safety valves are designed to release excess gas if the gas pressure rises above the normal level. The safety valves close automatically when the gas pressure drops to normal level. This feature prevents excess gas accumulation in the battery. The low-pressure ventilation system, combined with efficiency, creates a safe and leak-proof structure.