That fractured Twist tube on that Lefever H Grade is a bit creepy. Is there a story to go with that photo? That looks more like corrosion than a failure. But, I believe that Dr. Gaddy (amongst others) maintained that Twist was the least-strong of all the braided tubes, ranging from Twist(or Skelp), to Damascus (2,3,and 4 bar), to Laminated Steel. There also seems to be a bias in the literature towards English fabrication over the Belgium-made tubes (but, of course, most of those publications are of English origin).