CFL Ballast, Ballast Type MagneticInput Watts 27, Voltage 277, Min. Starting Temp. 0 Degrees F, Base Type 2 PinNumber of Lamps 2, Ballast Factor 0.92, Power Factor Greater Than 0.90, Length 4-3/4 In., Width 2-7/32 In., Height 1-5/8 In., Wiring Type Series, Light Output NormalNumber of F13BX Lamps 2, Number of F13DBX Lamps 2