18W 2ft Daylight 6500K full spectrum fluorescent T8 tube light bulb with near perfect colour rendering index (Ra) of 98%.Fitted with a standard sized G13 2-pin (13mm apart) caps to both ends.The Activa 172 range are ideal for use in design, print and publishing where excellent light quality and supreme colour rendering are paramount. Also emitting a tiny amount of UV light, these light bulbs are the closest available alternative to natural daylight and ideal for counteracting the effects of SAD. Osram BIOLUX sometimes supplied.For maximum performance and efficiency from your new fluorescent tube, we recommend you replace the fluorescent starter at the same time.Need more help in choosing a suitable fluorescent tube? Read our guide Choosing Flourescent Tubes and our guide to Flourescent Starters.