Iset is a Shetland marking. This particular marking usually appears not at birth like most marking, but within the first 2 years. Least tht's the way my sheep express it. White wool fibers appear in Moorit or Black fleeces beginning in the rear and moving up over the back. Iset changes the color of the fleece and gives more interest in Shetland wool. This skein 9 1/2 ozs., 154 yards, DK weight has the look of Cafe Mocha. A lovely soft look and feel. See comparison of Shetland wool coloring below.