The Tridonic PC 1x38-34 HO DD COMBO is a combination electronic ballast and emergency lighting unit to run 1 x 38w 2D compact fluorescent. They have a 3 hour rated duration and should be used with a 4 cell battery pack. These ballasts come with a 5-year warranty. Tridonic article number: 89899933Dimensions: 123 x 79 x 31mm