ST 2LNBFPRS 1L 17W NBFIS ML B6

4′ Stairwell, 4′ Normal Ballast Factor (2-Lamp Length and PRS Ballast), 17W 2′ T8 Normal Ballast Factor (1-Lamp Length and IS Ballast), Perforated Metal, 120V TCP 700 lumen 90 minute emergency ballast