Keystone F54T5 4 Lamp Ballast Keystone Replacement Ballast - KTEB-454HO-UV-PS Primary Lamp Type: F54T5HO - Number of Lamps 1,2,3,4 Program Start, 120-277 Volt Approximate Measurements: Length 16.73" Width 1.70" Height 1.18" New Updated Case Style - New Manufacturer Logo