Only 4% elastane but the material is flexible and adapts perfectly to the size and shape of the chair.
After a few days, the covers are in place.
The fabric is not particularly heavy but is not "too late" as noted by other reviewers. This looks a bit like a fitted sheet but thicker. See the use and with time ...
I also like the finish and not completely united with relief or crumpled as on other models.
The gray color is very beautiful and modern.
No regrets for this purchase despite the price a little high for my taste.