Power Sentry® batteries fit in the tightest of applications, including low profile lensed troffers, downlighting and industrial lighting fixtures. They also feature an innovative Quick-Disconnect wiring harness that makes field maintenance and upgrades quick and easy. Specification grade emergency ballast to operate one or two lamps (4 ft or shorter) or one 8 ft lamp. Factory or field installed inside or outside (field only) fluorescent fixture to operate lamp(s) at a reduced light output, providing optimum glare free illumination for a minimum of 90 min upon interruption of normal power.