I agree with Kelly. (To my knowledge) Log made all of the Herter's shafts and their #7 was marked as a Farbenglas G when built for Herters. I still have a few of those. That would make H and I the same as Log 8s and 9s, and J would likely equate to a 10. I likely have a couple of Microflite 7s around here as well, and can check the static spines, if it's real important to you. I used both in several spines for a number of years and did not find a significant difference in spine between microflite and log shafts. I did believe microflite shafts to be tougher than Log. However, Log shafts performed about the same.