From the Quince & Co website:

Quince & Company Kestrel is a new take on a simple linen yarn. We took the same Belgium-grown organic linen that we use in our little Sparrow and spun it this time in a ribbon structure. Kestrel knits up quickly at 3 ½ to 4 stitches to the inch. Its flat surface adds a slight texture to simple knit and purl stitches. But we think the best thing about it is its incredible drape. Like all things linen, woven or knitted, Kestrel only gets better as you wash and wear it.

Care for Kestrel:
Our linen yarn is machine washable in cold water. Lay it flat to dry and iron, if necessary, with a medium-hot iron. The more you wash a linen piece, the softer and drapier it becomes. We (and many knitters) have had success with drying our linen pieces in the dryer without shrinkage. As each machine is different, we strongly recommend that you test drying time, heat level, etc. on your gauge swatch.