The Trestar 924 is a three-phase uninterruptible power supply for central emergency lighting systems that provides a 90-minute backup during blackouts. The valve-regulated, lead-acid battery has a 10-year design-life at 77 degrees, and fully recharges in less than 72 hours. Accessed from the front and top, dimensions vary based on capacity, which ranges from 10 to 75 kW. www.stacoenergy.com