Slimline high output (HO) fluorescent T5 tube light bulb. Ideal for use in offices with high ceilings and for applications where a high luminous flux is required. For use with electronic control gear only. N.B. Listed as a 549mm tube but is actually 563mm INCLUDING the pins.Fitted with standard G5 2-pin (5mm apart) caps to both ends. Need more help in choosing a suitable fluorescent tube? Read our guide Choosing Flourescent Tubes and our guide to Flourescent Starters.