High Bay LED Light 237W grow Lighting 4000K. This is item is referred to as retro fit. In the retro fit, the E39 socket is used and the ballast is un wired and by passed. This is a new light with new E39 light base included Be sure to compare specs closely, this light manufacturer makes different models with variances in the specs... If you intend to use these for growing plants, these are the highest rated power and these have the increased wraparound lense, up light dispersion..... Dont be fooled by similar looking different models or alikes, check the comparisons in the data sheet. These are the highest lumin in in the E39 spcket size.