Sylvania 40W T5 Pentron Circline Fluorescent Bulb - FPC40/835 - Description: 40W, T5 Pentron Circline fluorescent lamp, 3500K color temperature, rare earth phosphor, 82 CRI. Average Rated Life (hr) 12000, Base 2GX13 Bulb T5, Manufacture Sylvania. Part number Sylvania-20732 Sylvania 40W T5 Pentron Circline Fluorescent Bulb - FPC40/835