Interesting but also uninteresting as well.
Thermoplastische Polyurethane have interesting properties that are not just based on their rigidity - That’s why I keep my eyes open for TPUs that get even harder than 58D which you actual can get.
There are already methods for getting to 58A with real TPU with under-extrusion …:
The problem still is at Bambulab only which simply reject all types of TPU without apology as soon as you want to load it into the AMS - So the solutions have been there for a long time:
And because of the poor description of this new “Big Tree Tech” fillament, the fillament is useless at all… UV resistance? Resistance to solvents? Splitter properties? Standards met for possible residues? And so on… They can sell this on Amazon as far as I’m concerned. At least for me, just good enough for the trash can due to missing specification and 3 batch checks…