HD6018T has two types of quality. One is made from Taiwan TPU raw material, named HD6018TB. Another one is made from Germany TPU raw material, named HD6018TD.
HD6018TD has good anti-yellowing and anti-ageing performance. Its anti-yellowing class reaches to grade 4-5. Moreover, it has high quality transmissivity. Compared with TD, HD6018TB don't have such good performance. Its anti-yellowing class is in grade 3-4. As to transmissivity, TB may have some spot on surface.
However, both TB and TD are smooth and pass Oeko-tex Standard 100 Certificate.