They took the same fabric used on all REBEL8 button-up flannels:

…special poly blend, ultra soft hand feel, minimal shrinking after washing/drying, zero wrinkling and no need to dry clean or iron ever, adjusted the fit slightly and added a full length front zipper, zip pocket and embroidery on chest. The Flannel Zip Shirt is now available on REBEL8.com. Model is 5′ 10″ 165 lbs and wearing a size large.

REBEL8 2825 South Sante Fe Avenue Vernon, California 90058