AC Delco Advantage Batteries feature an impact resistant plastic case for durability. They are Sealed Maintenance Free design with corrosion resistant terminals. Integral gas separators and flame arrestor vents prevent possible damage from outside sparks. Premium technology in the metal alloys, chemicals and design combine to ensure long life performance. Both positive and negative grids are Lead-Calcium alloy, maximising corrosion resistance, increasing cycle life and reducing water consumption to improve battery durability. Premium alloys and high-density paste for improved performance. Envelope Separator design helps eliminate shorting and corrode through to improve reliability and battery life. Sealed on three sides, the AC Delco Advantage Batteries separators are shaped like an envelope made of polyvinyl chloride. The Envelope Separators are puncture-resistant with a back web rib design to allow good electrolyte diffusion between the plates while preventing them from touching each other. This also improves acid circulation, allowing the battery to remain cooler, extending battery life. Manufactured with dozens of quality control checks to provide ACDelco quality.