Everything I've seen is for Bowens S-type, not L type. I'm not sure of any interchangeability using Balcar rings either, although they may work, or maybe not ... i dont have any laying around to test... same for Alienbees, in web pictures they "sort of" look the same but if they are not 6" (153mm-ish) they likely wont work.... This is so frustrating, there are so many of these strobes still in service, but nothing left for modifiers!