Sylvania 75173 SubstiTUBE Instant Start  4100K Compatible LED T8 Bulb, 4-Feet, Cool White 1600 to 2500 lumen output on ISL through ISH ballasts Compatible with instant start electronic T8 ballasts with input voltage of 120-277V and 347V No warm-up time instant-on with full light output and stable lamp color Long 50,000 hour life L70 Glass free and vibration and impact resistant with no UV emission