Philips Advance Optanium 40-Watt (F40T12) 1 or 2 Lamp T8 4 ft. 120/277-Volt Instant Start Electronic Fluorescent Replacement Ballast 520445 - The Home Depot
Reviews for Philips Advance AmbiStar 40-Watt (F40T12) 2 Lamp 4 ft. T12 120-Volt Rapid Start High Frequency Electronic Replacement Ballast | Pg 3 - The Home Depot
PHILIPS ADVANCE R-2S40-1-TP BALLAST, RAPID START, MARK III, 8-WIRE, 120V, 60HZ | eBay