They say.500 on them, but my spine tester says every gold tip I have put on it is stiffer than marked. The 3555's mostly ran about .450-.470.
The .400's show stiffer also. Most of them run .350-.370.
Every dz of GT shafts I have done has had some oddballs that were way off. These were all .003 shafts, none blems, and I have done LOTS of these shafts. The oddballs, some of whiuch were so far off they did not shoot worth a crsp from my setup, are the reason I quit shooting GT.
As a disclaimer, it has been a couple years since I have shot them, so things could have changed since then for the better. I hope so!
I have RAM spine tester set up for carbon shafts at 28" with a 1.94# weight.
Bisch