4ft 18w smd led t8 retrofit daylight 160d 1600lm the led t8 tube range is a direct replacement for a standard t8 fluorescent tube the led tube is a direct retrofit for the fluorescent tube in a magnetic ballast or switch start luminaire without the need to bypass the ballast or remove the starter in order for these tubes to work in a high frequency or electronic ballast luminaire a modification needs to be made this involves bypassing the control gear in the fitting and you may require a elec