Thank you for your posts. First of all JF125H is 16cm instead of 16mm. My mistake.
I think you are right. "J" of JF125H is for Japan, I guess.
Do you know if JBL has ever made any 16cm (about 6.3inch) drivers other than JF125H? If so,I might be able to find alternative recone kit that meets the size spec of JF125H.
Best,