This is a Bright Source Emergency 4ft Single 20w LED Batten Fitting designed to replace traditional 1 x 36w T8 Fluorescent tube fittings offering savings of 53%. New and improved, this fitting has the option to pick you colour between either warm white (3000k), cool white (4000k) or daylight (6000k) via a simple switch inside the main body of the fitting. All the specification of the standard batten is still applicable in normal maintained running mode. The emergency backup pack is invisibly integrated into the body of the batten. These fittings come complete with LED Emergency inverter, rechargeable emergency battery stick and Green LED indicator. With an average life span over 50,000 hours, this averages at over 10 years based on normal use, significantly reducing maintenance costs. The batten also boasts a lumen output of 2725 lumens meaning it has an extremely high lumen per watt of 131. The 4ft batten fittings are often used in warehouses and factories as well as being used to lig