Not sure off hand, but it came with 2 sets of shims if i remember correctly. So i'm guessing 25.4 & 26.0
Cheers. Looking at the pics, one looks relatively slim, I assume to shim down to 26mm The other looks a little thicker, which I hope would shim to 22mm...
@spotter
Look good! What size can the shims reduce the clamp down to? Their site doesn't specify and I'm hoping to fit on to TT extensions...