4050300517797 18 W T8 Fluorescent Tube, 1350 lm, 600mm. Osram Lumilux T8 fluorescent tubes are energy efficient fluorescent lamps. They meet standard T8 sizing, which means they are tubular with a 26 mm diameter. These fluorescent tubes feature a G13 base. This series is available in a range of colours from 2700 K all the way through to 8000 K.