ROBERTSON 3P10112 Fluorescent mBallast for 2 CFT13W/GX23 or CFQ13W/GX23 CFL Lamps, Preheat Start, 277Vac, 60Hz, Normal Ballast Factor, HPF, Model HP21327SP CM (Replaces Robertson 3M10113, HP21327SP /C) Save by ordering the Quik-Pak of 10 individually packaged ROBERTSON 2P10112 Offering the broadest ballast/LED Driver line available on Amazon. Go to RobertsonDirect.com for complete technical data. Take advantage of Robertson's 60 years of electronic design and quality manufacturing experience. Robertson warrants product will be free from defects in material or workmanship from date of manufacture when properly installed and under normal conditions of use.