Characters: 1. Assembe tightly, so the active material could not losen easily to longer the service life; 2. Long shelf life, about 12 months. 3. No charging after adding acid. 4. The grid is anti corrosion to ensure the long service life. 5. The RC (Reserved Capacity) is enough when the power is off. 6. Approved UL&CE; Specification: 1. Shelf Life: 12 months for dry battery, 6 months for maintenance free battery. 2. Gurantee Time: 12 months. 3. Low discharge rate, high discharge power, long service life.