GE Lighting 89712 GEM120TC120DIY LFL Magnetic Rapid Start Ballast for 1- F20T12, F15T8, F15T12, F14T12 Mount length: (M) 6.0-Inch / Mount slots: (MS) 0.3-Inch GE's ballasts are among the highest energy-efficient ballasts available For 1- F20T12, F15T8, F15T12, F14T12 Starting method: Trigger start Ballast type: Magnetic