I have bought several lots of different brands from e-bay. I do get polyester. Rayon is another one you will see a lot of. The difference is that Rayon has a brighter shine, but frays easier. The polyester I have shines quite well. What I have is all 40 wt. Some seem stronger than others. I have bought from Frim, radiantthreads, and abc all-embroidery, on e-bay.