Arc9 = 3U/2U; "light feel carbon" Arc9FL = 4U; "toughlex" Not sure, but the balance may be a little different too. It's possible the original Arc9 may be discontinued, as it doesn't appear on the latest chart from Yonex: http://www.badmintoncentral.com/forums/showthread.php?4389-Yonex-selection-chart/page15
Arc9FL also comes in 3U as well. I can confirm CD version is 3U since I saw it myself as it is instock at the local store as of last Wednesday.
There was another chart at the bottom . Another change: little pink diamonds instead of little pink hearts
BP = Badminton PSU, a japanese shop with their own special edition of regular ARC9 (which I have already posted twice now but no one seems to take notice . It has already been out since April and won't be available anywhere else or maybe the odd one purchased from there. If you look carefully it still has hearts)
Ohh i just got it lmfao thanks for the info i knew if i bump one more time someoen would tell me lmfao
but but whats the different between toughlex and light feel carbon, when i read the description the both provide more flex and power , but light feel carbon also has control
Just keep in mind. Arc 9 FL is also available in 3U as well. CD coded is 3U as I saw in person myself about over a week ago.