The SunDrop XR-U head can be host to a number of LED's. In terms of High CRI, it can be host to either the Nichia 083B as originally offered or host to the Nichia 119. The 119 will output more lumens than the 083B. As for brightest LED though, that would be the Cree XM-L which is not a high CRI LED but certainly bright! If you are willing to accept my guesses on lumens I would go with 60 for the 083B, 90 with the 119 and maybe 180 with the XM-L LED's.