I don't actually know - Modern is funny about what it sometimes leaves out in its descriptions. I will say it's extremely smooth cloth - your fingers can just barely discern surface texture. If it was much finer it would start to take on a sheen, which I don't like. For the casual, check, button down shirt I ordered, it's at the limits of what I'd want.
After laundering and drying (gently) the shirt, it fits wonderfully, but the darn thing is about 4" too short in the body. This has to be an oversight on someone's part as every other measurement is correct to within about 1/8" of what I specified. All the important stuff above the waterline is fine, but if I bend over to tie my shoes I'll be tucking. I emailed them - I wonder if I'll get a free shirt. It wasn't my intention, but I won't say no.
Stitching and construction are the equal, if not the superior of the shirts I've been getting. Scary straight single needle work. The collar buttons are cut from the same thickness as the front buttons, which makes them look almost square in profile - a little odd, but not objectionable.
Shirt ordered 5/26, delivered to my door 6/05. Dayum...