I recently had a 712U 3 iron with a KBS C-taper Stiff (120g) shaft in it. It was awesome hitting it off the tee box when it was a must to hit a narrow fairway. I got rid of it because I ended up getting the new 816 H1, however, after hitting the new T-MB I just ordered a 3 iron with the same shaft I had in the 712U. I have also contemplated using the C-taper lite to get a little higher ball flight, the x-flex is the same weight as the normal C-taper stiff shaft I have been using in my AP2's.