Flicker free start 1-100% dimming and constant light output this Twin High Frequency HE Ballast from Huco Electronics is a trusted and reliable option for 2 x 21 Watt T5 Fluorescent lamps. With a 50000 hour service life and a 60% reduction in energy consumption compared to conventional ballasts this is a trusted control gear for fluorescent lighting in offices supermarkets public buildings and educational establishments. Additional features include silent buzz free operation automatic shutdown at end of life and smooth warm lamp start.